25 results on '"Bhamra, S."'
Search Results
2. Systematic mutagenesis of the mouse prion protein to identify critical regions for the efficient propagation of prions
- Author
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Bhamra, S. K. and Jat, P.
- Subjects
612.8 - Abstract
The aim of this study was to systematically investigate the contributions of various amino acids within the prion protein, on prion propagation. To test this in a cellular system, we used a sub-cloned population of N2a cells (PK1) that are highly susceptible to RML mouse prions. A library of stable PK1 cells was generated, which expressed the full length mouse prion protein (moPrP) bearing either point, double, or triple alanine replacements. The effects these changes in the prion protein sequence had on the ability of PK1 cells to propagate RML was tested using a previously established cell based assay. We found that: (i) in the unstructured region of the protein, alanine replacements in CC2 region 90-111 of the prion protein severely diminish, but do not abrogate the ability of cells to propagate prions whilst substitutions K23A.K24A.R25A and Q41A exerted a moderate inhibitory effect on propagation; (ii) alanine replacements in CC2 displayed a dominant negative effect by imposing their propagation inhibition phenotype in the presence of the wild-type protein; (iii) the diminished propagation abilities of cells expressing CC2 alanine mutants were a result of these cells being less susceptible to infection than their wild-type counterparts (iv) all alanine replacements tested in the structured region of the protein appeared to hamper prion propagation, regardless of their positioning within this globular domain. Taken together, these results suggest that integrity of the structured region is vital for successful prion propagation, and that although the flexible region of the prion protein alone (residues 23-111), does not exclusively confer infectivity and/or propagative capacity, charge interactions in this region govern the efficacy with which propagation ensues.
- Published
- 2014
3. Screening for atrial fibrillation in care homes using pulse palpation and the AliveCor Kardia Mobile® device: a comparative cross-sectional pilot study
- Author
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Savickas, V., primary, Stewart, A. J., additional, Short, V. J., additional, Mathie, A., additional, Bhamra, S. K., additional, Veale, E. L., additional, and Corlett, S. A., additional
- Published
- 2023
- Full Text
- View/download PDF
4. A RANDOMISED CONTROLLED STUDY OF THE CLINICAL OUTCOME OF ROTATOR CUFF REPAIRS AT 6 AND 12 MONTHS
- Author
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Wallace, W. A., Kelly, I. G., Bhamra, S. M., Calvert, P., Levy, O., and Wheeldon, J.
- Published
- 2001
5. Empowering pharmacy professionals to enhance public health nutrition: a mixed methods study.
- Author
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Acar, G., Frost, R., Bhamra, S., and Heinrich, M.
- Abstract
Unhealthy dietary patterns stand as the foremost risk factor for noncommunicable disease- associated morbidity and mortality(1). As widely accessible healthcare providers, pharmacy professionals' potential to catalyze improvements in public health nutrition is substantial, offering a means to combat the escalating epidemic of obesity and NCDs through tailored interventions, services, and education(2 , 3). Our study employed a mixed-methods approach to assess the role of pharmacy professionals in promoting nutrition advice and healthy dietary practices. An online questionnaire (N=200) was designed and conducted to evaluate pharmacy professionals' nutrition knowledge, the advice given in various diet-related conditions (e.g. obesity, type 2 diabetes, cardiovascular disease risk factors, malnutrition, sustainable diets), practices in delivering diet- related guidance within their routine practice and perceived roles and future ambitions of pharmacy professionals towards nutrition counselling, yielding both quantitative and qualitative insights. Subsequently, qualitative interviews and focus group discussions (N=19) were conducted, engaging pharmacists, nutritionists and dietitians to gather insights essential for the development of a comprehensive nutrition toolkit tailored for pharmacy practice. These interviews delved deeper into the subject, with the goal of designing a nutrition toolkit that empowers pharmacists with the knowledge, tools, and resources needed to play a more active and impactful role in promoting nutrition and healthy lifestyle practices among their patients. Thematic analysis was conducted, and emerging themes and subthemes were identified. Our findings indicate that a significant portion of participants in our study are involved in providing nutrition and diet advice for various health conditions. The majority of pharmacists considered diabetes programmes having a high level of importance (84%), followed by weight management services (78%), hypertension management (86%), and healthy diet campaigns (63.5%). However, our knowledge and confidence rating questions revealed a significant gap in training and a clear need for educational materials tailored for pharmacists to enhance their ability to provide nutrition advice effectively. Key themes identified in open-text questions were referrals and collaboration, training and education needs, wider needs (changes in the public health system, materials/resources, integration and implementation of nutrition in pharmacy practice) and perceived roles as pharmacists in providing nutrition advice (patient support, feeling responsible, specialised focus areas). Qualitative findings underscore the pressing demand for nutrition training and education to deliver comprehensive services, as well as the necessity for collaborative efforts with dietitians and nutritionists to ensure effective care and the improvement of referral pathways in pharmacy practice. This research contributes to the advancement of public health nutrition by recognizing the potential role of pharmacy professionals as key players in the dissemination of nutrition knowledge and fostering healthy behaviours within the community. The results will guide us in the collaborative development of a nutrition toolkit tailored for pharmacy practice, employing a co-design approach. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
6. National survey of UK general practice pharmacy services
- Author
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Savickas, V, primary, Foreman, E, primary, Iqbal, M, primary, Ladva, A, primary, Bhamra, S K, primary, Sharma, R, primary, and Corlett, S A, primary
- Published
- 2019
- Full Text
- View/download PDF
7. P6145Atrial fibrillation screening in care homes by clinical pharmacists using pulse palpation and single-lead ECG: a feasibility study
- Author
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Savickas, V, primary, Stewart, A J, additional, Short, V J, additional, Mathie, A, additional, Bhamra, S K, additional, Corlett, S A, additional, and Veale, E L, additional
- Published
- 2019
- Full Text
- View/download PDF
8. P4470Atrial fibrillation screening in general practice by clinical pharmacists using pulse palpation and single-lead ECG during the influenza vaccination season: a multi-site feasibility study
- Author
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Savickas, V, primary, Stewart, A J, additional, Mathie, A, additional, Bhamra, S K, additional, Corlett, S A, additional, and Veale, E L, additional
- Published
- 2018
- Full Text
- View/download PDF
9. DNA authentication of tulsi (Ocimum tenuiflorum) using the nuclear ribosomal internal transcribed spacer (ITS) and the chloroplast intergenic spacer trnH-psbA
- Author
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Bhamra, S, primary, Heinrich, M, additional, Howard, C, additional, Johnson, M, additional, and Slater, A, additional
- Published
- 2015
- Full Text
- View/download PDF
10. DNA authentication of Tulsi; the cultural and medicinal value of Ocimum species among diasporic South Asian communities in the UK
- Author
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Bhamra, S, primary, Heinrich, M, additional, Howard, C, additional, Johnson, M, additional, and Slater, A, additional
- Published
- 2014
- Full Text
- View/download PDF
11. The retention of older people in longitudinal studies: a review of the literature.
- Author
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Bhamra S, Tinker A, Mein G, Ashcroft R, and Askham J
- Abstract
Research that follows people over a period of time (longitudinal or panel studies) is increasingly recognised as of great importance in helping us to understand the ageing process and changes over time in the lives of older people. If people drop out of studies -- which older people are more likely to do -- the value of the study diminishes. This research draws on evidence from ongoing and previous longitudinal studies of people aged 55 and over to examine what factors encourage the retention of participants and what causes them to drop out. The research is synthesising existing evidence, drawing together the experiences of researchers involved in longitudinal studies, and collecting some new evidence about the views of survey participants. This article reports on the first part of the research by drawing together evidence from other studies. These show that there are some factors that are related to attrition whereas for others the evidence is mixed. Methods employed by these studies to reduce attrition and retain participants are examined. It must be noted that apart from the consistent finding that attrition is associated with age, education, socio-economic status and cognitive impairment, not all studies examined the same variables; some only being explored by one study. This makes it difficult to draw any further conclusions and indicates that attrition needs to be addressed in a uniform manner by more studies. This article identifies some implications for policy-makers and practitioners. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
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12. Structure and function of plasmid ColK
- Author
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Tacon, W., primary, Bhamra, S., additional, Sunar, B., additional, and Sherratt, D., additional
- Published
- 1981
- Full Text
- View/download PDF
13. Co-design of 'Ways of Being', a web-based experience to optimise online arts and culture for mental health in young people.
- Author
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Syed Sheriff RJ, Sinclair E, Young J, Bhamra S, Chandler L, Arachchige T, Adams H, Bonsaver L, Riga E, Bergin L, Mirtorabi N, Abuelgasim L, Beuchner H, and Geddes J
- Abstract
Aims and Method: We aimed to co-design an intervention optimising the benefits of online arts and culture for mental health in young people for subsequent testing in a trial. Co-design followed the double diamond phases of design, discover, define, develop and deliver., Results: Navigating the views of all co-designers to produce a testable resource demanded in-depth understanding, and frequent iterations in multiple modalities of the theoretical basis of the intervention, amplification of youth voice and commitment to a common goal., Clinical Implications: Co-design with a broad range of collaborators with a shared vision was valued by young co-designers and produced an effective intervention. Co-design allowed the theoretical basis to be followed and refined to create an engaging, practical and testable web experience, aiming to optimise the mental health benefits of online arts and culture for young people in a randomised controlled trial.
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- 2024
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14. Prion Propagation is Dependent on Key Amino Acids in Charge Cluster 2 within the Prion Protein.
- Author
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Bhamra S, Arora P, Manka SW, Schmidt C, Brown C, Rayner MLD, Klöhn PC, Clarke AR, Collinge J, and Jat PS
- Subjects
- Animals, Mice, Leucine chemistry, Leucine genetics, Amino Acid Substitution, Protein Domains, Cell Line, Alanine chemistry, Alanine genetics, Prion Proteins chemistry, Prion Proteins genetics
- Abstract
To dissect the N-terminal residues within the cellular prion protein (PrP
C ) that are critical for efficient prion propagation, we generated a library of point, double, or triple alanine replacements within residues 23-111 of PrP, stably expressed them in cells silenced for endogenous mouse PrPC and challenged the reconstituted cells with four common but biologically diverse mouse prion strains. Amino acids (aa) 105-111 of Charge Cluster 2 (CC2), which is disordered in PrPC , were found to be required for propagation of all four prion strains; other residues had no effect or exhibited strain-specific effects. Replacements in CC2, including aa105-111, dominantly inhibited prion propagation in the presence of endogenous wild type PrPC whilst other changes were not inhibitory. Single alanine replacements within aa105-111 identified leucine 108 and valine 111 or the cluster of lysine 105, threonine 106 and asparagine 107 as critical for prion propagation. These residues mediate specific ordering of unstructured CC2 into β-sheets in the infectious prion fibrils from Rocky Mountain Laboratory (RML) and ME7 mouse prion strains., (Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.)- Published
- 2023
- Full Text
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15. The enpp4 ectonucleotidase regulates kidney patterning signalling networks in Xenopus embryos.
- Author
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Massé K, Bhamra S, Paroissin C, Maneta-Peyret L, Boué-Grabot E, and Jones EA
- Subjects
- Animals, Embryo, Nonmammalian embryology, Embryonic Development, Gene Regulatory Networks, Kidney embryology, Phosphoric Diester Hydrolases genetics, Xenopus Proteins genetics, Xenopus laevis growth & development, Xenopus laevis metabolism, Body Patterning genetics, Kidney physiology, Phosphoric Diester Hydrolases physiology, Signal Transduction, Xenopus Proteins physiology, Xenopus laevis genetics
- Abstract
The enpp ectonucleotidases regulate lipidic and purinergic signalling pathways by controlling the extracellular concentrations of purines and bioactive lipids. Although both pathways are key regulators of kidney physiology and linked to human renal pathologies, their roles during nephrogenesis remain poorly understood. We previously showed that the pronephros was a major site of enpp expression and now demonstrate an unsuspected role for the conserved vertebrate enpp4 protein during kidney formation in Xenopus. Enpp4 over-expression results in ectopic renal tissues and, on rare occasion, complete mini-duplication of the entire kidney. Enpp4 is required and sufficient for pronephric markers expression and regulates the expression of RA, Notch and Wnt pathway members. Enpp4 is a membrane protein that binds, without hydrolyzing, phosphatidylserine and its effects are mediated by the receptor s1pr5, although not via the generation of S1P. Finally, we propose a novel and non-catalytic mechanism by which lipidic signalling regulates nephrogenesis., (© 2021. The Author(s).)
- Published
- 2021
- Full Text
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16. Product authenticity versus globalisation-The Tulsi case.
- Author
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Jürges G, Sahi V, Rios Rodriguez D, Reich E, Bhamra S, Howard C, Slater A, and Nick P
- Subjects
- DNA Barcoding, Taxonomic, Ocimum sanctum genetics, Plastids genetics, Fraud prevention & control, Internationality, Ocimum sanctum classification
- Abstract
Using the Indian medicinal plant Tulsi (Holy Basil) as a case study, we have tested to what extent the discrepancy between vernacular and scientific nomenclature can be resolved, whether the presumed chemical diversity underlying the medicinal use of Tulsi has a genetic component, and whether it is possible to detect this genetic component using genetic barcoding markers. Based on four plastidic markers, we can define several haplotypes within Ocimum that are consistent across these markers. Haplotype II is congruent with O. tenuiflorum, while haplotype I extends over several members of the genus and cannot be resolved into genetically separate subclades. The vernacular subdivision of Tulsi into three types (Rama, Krishna, Vana) can only be partially linked with genetic differences-whereby Rama and Krishna Tulsi can be assigned to O. tenuiflorum, while Vana Tulsi belongs to haplotype I. This genetic difference is mirrored by differences in the profiles of secondary compounds. While developmental state and light quality modulate the amplitude to which the chemical profile is expressed, the profile itself seems to be linked with genetic differences. We finally develop an authentication assay that makes use of a characteristic single nucleotide polymorphism in one of the barcoding markers, establishing a differential restriction pattern that can be used to discriminate Vana Tulsi., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2018
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17. The lysophosphatidic acid (LPA) and sphingosine-1-phosphate (S1P) receptor gene families: cloning and comparative expression analysis in Xenopus laevis.
- Author
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Massé K, Kyuno J, Bhamra S, and Jones EA
- Subjects
- Amino Acid Sequence, Animals, Cloning, Molecular, Embryo, Nonmammalian embryology, Embryo, Nonmammalian metabolism, Female, Gene Expression Profiling, Gene Expression Regulation, Developmental, In Situ Hybridization, Male, Molecular Sequence Data, Oocytes metabolism, Phylogeny, Protein Isoforms classification, Protein Isoforms genetics, Receptors, Lysophosphatidic Acid classification, Receptors, Lysosphingolipid classification, Reverse Transcriptase Polymerase Chain Reaction, Sequence Homology, Amino Acid, Species Specificity, Xenopus embryology, Xenopus genetics, Xenopus laevis embryology, Multigene Family, Receptors, Lysophosphatidic Acid genetics, Receptors, Lysosphingolipid genetics, Xenopus Proteins genetics, Xenopus laevis genetics
- Abstract
Sphingosine-1-phosphate (S1P) and lysophosphatidic acid (LPA) are endogenous bioactive lipids which mediate a variety of biological cell responses such as cell proliferation, migration, differentiation and apoptosis. Their actions are mediated by binding to the G-protein-coupled endothelial differentiation gene (Edg) receptor subfamily, referred to as S1P1-5 and LPA1-5, and regulate a variety of signalling pathways involved in numerous physiological processes and pathological conditions. Their importance during embryogenesis has been demonstrated by the generation of knock-out mice and specific roles have been assigned to these receptors. However, potential functional redundancy and the lethality of some mutants have complicated functional analysis in these models. Here we report the cloning of the S1P and LPA receptors in Xenopus laevis and tropicalis. Phylogenetic analyses demonstrate the high level of conservation of these receptors between amphibian and other vertebrate species. We have conducted a comparative expression analysis of these receptors during development and in the adult frog, by both RT-PCR and whole mount in situ hybridisation. In particular, we show that S1P1, 2 and 5 display distinct embryonic specific expression patterns, suggesting potentially different developmental roles for these receptors, and therefore for their ligands, during amphibian embryogenesis.
- Published
- 2010
- Full Text
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18. Ectophosphodiesterase/nucleotide phosphohydrolase (Enpp) nucleotidases: cloning, conservation and developmental restriction.
- Author
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Massé K, Bhamra S, Allsop G, Dale N, and Jones EA
- Subjects
- Amino Acid Sequence, Animals, Cloning, Molecular, Computational Biology, Conserved Sequence, Embryo, Nonmammalian metabolism, In Situ Hybridization, Molecular Sequence Data, Nucleotidases genetics, Phylogeny, RNA Probes, RNA, Messenger genetics, RNA, Messenger metabolism, Reverse Transcriptase Polymerase Chain Reaction, Sequence Homology, Amino Acid, Xenopus classification, Embryo, Nonmammalian cytology, Gene Expression Regulation, Developmental, Nucleotidases metabolism, Xenopus embryology, Xenopus metabolism
- Abstract
Ectonucleotidase proteins occupy a central role in purine signalling regulation by sequentially hydrolysing ATP to ADP and to adenosine. The ENPP ( or PDNP) gene family, which encodes ectophosphodiesterase/nucleotide phosphohydrolases, is a subfamily of these enzymes, which consists of 7 members in mammals. These proteins catalyse the generation of bioactive lipids, placing the ENPP enzymes as key regulators of major physiological signalling pathways and also important players in several pathological conditions. Here we report the cloning of all the members, except enpp5, of the enpp family in Xenopus laevis and tropicalis. Phylogenetic analyses demonstrate the high level of conservation of these proteins between amphibian and other vertebrate species. During development and in the adult frog, each gene displays a distinct specific expression pattern, suggesting potentially different functions for these proteins during amphibian embryogenesis. This is the first complete developmental analysis of gene expression of this gene family in vertebrates.
- Published
- 2010
- Full Text
- View/download PDF
19. The lmx1b gene is pivotal in glomus development in Xenopus laevis.
- Author
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Haldin CE, Massé KL, Bhamra S, Simrick S, Kyuno J, and Jones EA
- Subjects
- Animals, Cell Culture Techniques, DNA-Binding Proteins genetics, DNA-Binding Proteins metabolism, Embryo, Nonmammalian, Gene Expression Regulation, Developmental drug effects, Gene Expression Regulation, Developmental genetics, Gene Targeting, Homeodomain Proteins biosynthesis, Homeodomain Proteins genetics, Homeodomain Proteins metabolism, In Situ Hybridization, Kidney cytology, LIM-Homeodomain Proteins, Microinjections, RNA Interference, RNA, Messenger metabolism, RNA, Messenger pharmacology, Reverse Transcriptase Polymerase Chain Reaction, Transcription Factors biosynthesis, Transcription Factors genetics, Xenopus Proteins genetics, Xenopus Proteins metabolism, Xenopus laevis genetics, Homeodomain Proteins physiology, Kidney embryology, Kidney metabolism, Transcription Factors physiology, Xenopus laevis embryology
- Abstract
We have previously shown that lmx1b, a LIM homeodomain protein, is expressed in the pronephric glomus. We now show temporal and spatial expression patterns of lmx1b and its potential binding partners in both dissected pronephric anlagen and in individual dissected components of stage 42 pronephroi. Morpholino oligonucleotide knock-down of lmx1b establishes a role for lmx1b in the development of the pronephric components. Depletion of lmx1b results in the formation of a glomus with reduced size. Pronephric tubules were also shown to be reduced in structure and/or coiling whereas more distal tubule structure was unaffected. Over-expression of lmx1b mRNA resulted in no significant phenotype. Given that lmx1b protein is known to function as a heterodimer, we have over-expressed lmx1b mRNA alone or in combination with potential interacting molecules and analysed the effects on kidney structures. Phenotypes observed by over-expression of lim1 and ldb1 are partially rescued by co-injection with lmx1b mRNA. Animal cap experiments confirm that co-injection of lmx1b with potential binding partners can up-regulate pronephric molecular markers suggesting that lmx1b lies upstream of wt1 in the gene network controlling glomus differentiation. This places lmx1b in a genetic hierarchy involved in pronephros development and suggests that it is the balance in levels of binding partners together with restricted expression domains of lmx1b and lim1 which influences differentiation into glomus or tubule derivatives in vivo.
- Published
- 2008
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20. Purine-mediated signalling triggers eye development.
- Author
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Massé K, Bhamra S, Eason R, Dale N, and Jones EA
- Subjects
- Adenosine Diphosphate metabolism, Adenosine Triphosphatases deficiency, Adenosine Triphosphatases genetics, Adenosine Triphosphatases metabolism, Adenosine Triphosphate metabolism, Animals, Choristoma genetics, Choristoma metabolism, Embryo, Nonmammalian embryology, Embryo, Nonmammalian metabolism, Eye Proteins genetics, Eye Proteins metabolism, Gene Expression Regulation, Developmental, Homeodomain Proteins genetics, Homeodomain Proteins metabolism, Molecular Sequence Data, Nerve Tissue Proteins genetics, Nerve Tissue Proteins metabolism, PAX6 Transcription Factor, Paired Box Transcription Factors genetics, Paired Box Transcription Factors metabolism, Phenotype, Receptors, Purinergic P2 deficiency, Receptors, Purinergic P2 genetics, Receptors, Purinergic P2 metabolism, Receptors, Purinergic P2Y1, Repressor Proteins genetics, Repressor Proteins metabolism, Xenopus Proteins genetics, Xenopus Proteins metabolism, Xenopus laevis genetics, Homeobox Protein SIX3, Eye embryology, Eye metabolism, Purines metabolism, Signal Transduction, Xenopus laevis embryology, Xenopus laevis metabolism
- Abstract
A conserved network of eye field transcription factors (EFTFs) underlies the development of the eye in vertebrates and invertebrates. To direct eye development, Pax6, a key gene in this network, interacts with genes encoding other EFTFs such as Rx1 and Six3 (refs 4-6). However, the mechanisms that control expression of the EFTFs remain unclear. Here we show that purine-mediated signalling triggers both EFTF expression and eye development in Xenopus laevis. Overexpression of ectonucleoside triphosphate diphosphohydrolase 2 (E-NTPDase2), an ectoenzyme that converts ATP to ADP, caused ectopic eye-like structures, with occasional complete duplication of the eye, and increased expression of Pax6, Rx1 and Six3. In contrast, downregulation of endogenous E-NTPDase2 decreased Rx1 and Pax6 expression. E-NTPDase2 therefore acts upstream of these EFTFs. To test whether ADP (the product of E-NTPDase2) might act to trigger eye development through P2Y1 receptors, selective in Xenopus for ADP, we simultaneously knocked down expression of the genes encoding E-NTPDase2 and the P2Y1 receptor. This could prevent the expression of Rx1 and Pax6 and eye formation completely. We next measured ATP release in the presumptive eye field, demonstrating a transient release of ATP at a time that could plausibly trigger (once converted to ADP) expression of the EFTFs. This surprising role for transient purine-mediated signalling in eye development may be widely conserved, because alterations to the locus of E-NTPDase2 on human chromosome 9 cause severe head and eye defects, including microphthalmia. Our results suggest a new mechanism for the initiation of eye development.
- Published
- 2007
- Full Text
- View/download PDF
21. Anxa4 Genes are Expressed in Distinct Organ Systems in Xenopus laevis and tropicalis But are Functionally Conserved.
- Author
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Massé KL, Collins RJ, Bhamra S, Seville RA, and Jones EA
- Abstract
Anxa4 belongs to the multigenic annexin family of proteins which are characterized by their ability to interact with membranes in a calcium-dependent manner. Defined as a marker for polarized epithelial cells, Anxa4 is believed to be involved in many cellular processes but its functions in vivo are still poorly understood. Previously, we cloned Xanx4 in Xenopus laevis (now referred to as anxa4a) and demonstrated its role during organogenesis of the pronephros, providing the first evidence of a specific function for this protein during the development of a vertebrate. Here, we describe the strict conservation of protein sequence and functional domains of anxa4 during vertebrate evolution. We also identify the paralog of anxa4a, anxa4b and show its specific temporal and spatial expression pattern is different from anxa4a. We show that anxa4 orthologs in X. laevis and tropicalis display expression domains in different organ systems. Whilst the anxa4a gene is mainly expressed in the kidney, Xt anxa4 is expressed in the liver. Finally, we demonstrate Xt anxa4 and anxa4a can display conserved function during kidney organogenesis, despite the fact that Xt anxa4 transcripts are not expressed in this domain. This study highlights the divergence of expression of homologous genes during Xenopus evolution and raises the potential problems of using X. tropicalis promoters in X. laevis.
- Published
- 2007
- Full Text
- View/download PDF
22. Comparative genomic and expression analysis of the conserved NTPDase gene family in Xenopus.
- Author
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Massé K, Eason R, Bhamra S, Dale N, and Jones EA
- Subjects
- Amino Acid Sequence, Animals, Cloning, Molecular, DNA, Complementary chemistry, DNA, Complementary genetics, DNA, Complementary isolation & purification, Embryo, Nonmammalian embryology, Embryo, Nonmammalian metabolism, Female, Gene Expression Regulation, Developmental, In Situ Hybridization, Isoenzymes genetics, Male, Molecular Sequence Data, Multigene Family genetics, Phylogeny, Sequence Alignment, Sequence Analysis, DNA, Sequence Homology, Amino Acid, Time Factors, Xenopus embryology, Xenopus growth & development, Xenopus Proteins genetics, Xenopus laevis embryology, Xenopus laevis genetics, Xenopus laevis growth & development, Antigens, CD genetics, Apyrase genetics, Gene Expression Profiling, Genomics methods, Xenopus genetics
- Abstract
The purines, ATP and adenosine, are important signaling molecules in the nervous system. ATP is sequentially degraded to adenosine by the ectonucleotidase proteins. The NTPDase (or CD39) family is a subfamily of these enzymes, which consists of nine members in mammals. In Xenopus embryos, we have shown that ATP, and its antagonist adenosine, regulate the rundown of swimming and we therefore proposed that ectonucleotidase proteins are key regulators of locomotor activity. Here, we report the cloning of all nine members of the NTPDase family in Xenopus laevis and Xenopus tropicalis. Our phylogenetic analysis shows that this family is highly conserved between the frog species and also during vertebrate evolution. In the adult frog, NTPDase genes are broadly expressed. During development, all NTPDase genes, except for NTPDase8, are expressed and display a distinct specific expression pattern, suggesting potentially different functions of these proteins during embryogenesis of X. laevis.
- Published
- 2006
- Full Text
- View/download PDF
23. Cloning and characterisation of the immunophilin X-CypA in Xenopus laevis.
- Author
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Massé K, Bhamra S, Haldin CE, and Jones EA
- Subjects
- Amino Acid Sequence, Animals, Base Sequence, Cyclophilin A metabolism, DNA, Complementary, In Situ Hybridization, Molecular Sequence Data, Neural Crest abnormalities, Phenotype, Sequence Alignment, Xenopus laevis, Cyclophilin A genetics, Neural Crest embryology, Neural Crest enzymology
- Abstract
This paper reports the cloning of Xenopus laevis, cyclophilin A gene, X-CypA. This study is the first developmental and functional characterisation in vivo of cyclophilin A in a vertebrate. X-CypA belongs to the superfamily of the immunophilin/PPIase proteins that can bind the immunosuppressant drug Cyclosporin A. Sequence analysis showed that X-CypA is highly conserved during evolution. RT-PCR and in situ hybridisation analysis showed that X-CypA expression is regulated during development and its transcripts are found in three major expression domains: nervous system, sensory organs and pronephros. Over-expression of X-CypA in embryos, analysed by in situ hybridisation and RT-PCR, leads to an expansion and disorganisation of the neural crest domain.
- Published
- 2004
- Full Text
- View/download PDF
24. Effect of anti-ER antibodies within the ER lumen of living cells.
- Author
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Valle G, Bhamra SS, Martin S, Griffiths G, and Colman A
- Subjects
- Animals, Cell Line, Endoplasmic Reticulum immunology, Endoplasmic Reticulum ultrastructure, Estradiol, Female, Hybridomas, Immunohistochemistry, Immunologic Techniques, Liver immunology, Liver metabolism, Male, Mice, Microinjections, Microscopy, Fluorescence, Molecular Weight, Muramidase immunology, Muramidase metabolism, Oocytes immunology, Oocytes metabolism, Ovalbumin immunology, Ovalbumin metabolism, RNA, Messenger administration & dosage, Vitellogenins biosynthesis, Vitellogenins immunology, Xenopus laevis, Antibodies, Monoclonal biosynthesis, Endoplasmic Reticulum metabolism
- Abstract
We describe the production and partial characterization of 12 monoclonal antibodies raised against a preparation of endoplasmic reticulum membranes obtained from Xenopus laevis liver. Four of the antibodies cross-react with liver melanocytes; two of the antibodies recognize extracellular antigens, whilst the remaining six recognize antigens present in hepatocytes. The concentrations of these latter antigens increase markedly in livers stimulated by estrogen. Western blotting analysis revealed that the six anti-hepatocyte monoclonal antibodies recognize at least five different antigens whose molecular weights are 14K, 18K, 19K, 43K, and 125K. The possible functional involvement of the various antigens in the secretory pathway was investigated using Xenopus oocytes as a surrogate secretory system. The mRNAs coding for the monoclonal antibodies were injected into oocytes and the resulting immunoglobulin chains were translated and assembled into active anti-ER antibodies inside the lumen of the ER. The effect on secretion was then observed. Our data indicate that the binding of antibodies to most antigens of the endoplasmic reticulum membrane may result in a blockage of secretion.
- Published
- 1988
- Full Text
- View/download PDF
25. Post-translational modification of exogenous proteins in Xenopus laevis oocytes.
- Author
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Colman A, Bhamra S, and Valle G
- Subjects
- Animals, Female, Immunoglobulins biosynthesis, In Vitro Techniques, Ovalbumin biosynthesis, Peptides metabolism, Protein Sorting Signals, Proteins metabolism, RNA, Messenger metabolism, Oocytes metabolism, Protein Processing, Post-Translational, Xenopus laevis metabolism
- Published
- 1984
- Full Text
- View/download PDF
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