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Zinc finger of the cerebellum (Zic) proteins act as classic transcription factors to promote transcription of the Foxd3 gene during neural crest cell specification. Additionally, they can act as co-factors that bind proteins from the T-cell factor/lymphoid enhancing factor (TCF/LEF) family (TCFs) to repress WNT-ß-catenin-dependent transcription without contacting DNA. Here, we show that ZIC activity at the neural plate border is influenced by WNT-dependent SUMOylation. In the presence of high canonical WNT activity, a lysine residue within the highly conserved zinc finger N-terminally conserved (ZF-NC) domain of ZIC5 is SUMOylated, which reduces formation of the ZIC-TCF co-repressor complex and shifts the balance towards transcription factor function. The modification is crucial in vivo, as a ZIC5 SUMOincompetent mouse strain exhibits neural crest specification defects. This work reveals the function of the ZF-NC domain within ZIC, provides in vivo validation of target protein SUMOylation and demonstrates that WNT-ß-catenin signalling directs transcription at non-TCF DNA-binding sites. Furthermore, it can explain how WNT signals convert a broad region of Zic ectodermal expression into a restricted region of neural crest cell specification. [ABSTRACT FROM AUTHOR]

Zinc finger of the cerebellum (Zic) proteins act as classic transcription factors to promote transcription of the Foxd3 gene during neural crest cell specification. Additionally, they can act as co-factors that bind proteins from the T-cell factor/lymphoid enhancing factor (TCF/LEF) family (TCFs) to repress WNT-ß-catenin-dependent transcription without contacting DNA. Here, we show that ZIC activity at the neural plate border is influenced by WNT-dependent SUMOylation. In the presence of high canonical WNT activity, a lysine residue within the highly conserved zinc finger N-terminally conserved (ZF-NC) domain of ZIC5 is SUMOylated, which reduces formation of the ZIC-TCF co-repressor complex and shifts the balance towards transcription factor function. The modification is crucial in vivo, as a ZIC5 SUMOincompetent mouse strain exhibits neural crest specification defects. This work reveals the function of the ZF-NC domain within ZIC, provides in vivo validation of target protein SUMOylation and demonstrates that WNT-ß-catenin signalling directs transcription at non-TCF DNA-binding sites. Furthermore, it can explain how WNT signals convert a broad region of Zic ectodermal expression into a restricted region of neural crest cell specification. [ABSTRACT FROM AUTHOR]

Zinc finger of the cerebellum (Zic) proteins act as classic transcription factors to promote transcription of the Foxd3 gene during neural crest cell specification. Additionally, they can act as co-factors that bind proteins from the T-cell factor/lymphoid enhancing factor (TCF/LEF) family (TCFs) to repress WNT-ß-catenin-dependent transcription without contacting DNA. Here, we show that ZIC activity at the neural plate border is influenced by WNT-dependent SUMOylation. In the presence of high canonical WNT activity, a lysine residue within the highly conserved zinc finger N-terminally conserved (ZF-NC) domain of ZIC5 is SUMOylated, which reduces formation of the ZIC-TCF co-repressor complex and shifts the balance towards transcription factor function. The modification is crucial in vivo, as a ZIC5 SUMOincompetent mouse strain exhibits neural crest specification defects. This work reveals the function of the ZF-NC domain within ZIC, provides in vivo validation of target protein SUMOylation and demonstrates that WNT-ß-catenin signalling directs transcription at non-TCF DNA-binding sites. Furthermore, it can explain how WNT signals convert a broad region of Zic ectodermal expression into a restricted region of neural crest cell specification. [ABSTRACT FROM AUTHOR]

Abstract: The Zic genes encode zinc finger containing proteins that can bind proteins and DNA. The understanding of Zic molecular networks has been hampered by functional redundancy amongst family members, and because their loss-of-function phenotypes are indicative of a role in many signalling pathways. Recently molecular evidence has emerged confirming the pleiotropic nature of these proteins: they act both as classical transcription factors and as co-factors to directly and indirectly influence gene expression. It has long been known that germ-line mutation of the Zic genes in human and mouse causes a range of congenital disorders. Recently connections between Zic proteins and stem cell function have also emerged suggesting a role in adult onset diseases. The immediate challenge is to determine when and where these proteins act as transcription factors/co-factors during development and disease and how the switch between these roles is controlled. [Copyright &y& Elsevier]

Most mouse genetics laboratories maintain mouse strains that require genotyping in order to identify the genetically modified animals. The plethora of mutagenesis strategies and publicly available mouse alleles means that any one laboratory may maintain alleles with random or targeted insertions of orthologous or unrelated sequences as well as random or targeted deletions and point mutants. Many experiments require that different strains be cross bred conferring the need to genotype progeny at more than one locus. In contrast to the range of new technologies for mouse mutagenesis, genotyping methods have remained relatively static with alleles typically discriminated by agarose gel electrophoresis of PCR products. This requires a large amount of researcher time. Additionally it is susceptible to contamination of future genotyping experiments because it requires that tubes containing PCR products be opened for analysis. Progress has been made with the genotyping of mouse point mutants because a range of new high-throughput techniques have been developed for the detection of Single Nucleotide Polymorphisms. Some of these techniques are suitable for genotyping point mutants but do not detect insertion or deletion alleles. Ideally, mouse genetics laboratories would use a single, high-throughput platform that enables closed-tube analysis to genotype the entire range of possible insertion and deletion alleles and point mutants. Here we show that High Resolution Melt Analysis meets these criteria, it is suitable for closed-tube genotyping of all allele types and current genotyping assays can be converted to this technology with little or no effort. [ABSTRACT FROM AUTHOR]

Zinc finger of the cerebellum (Zic) proteins act as classic transcription factors to promote transcription of the Foxd3 gene during neural crest cell specification. Additionally, they can act as co-factors that bind proteins from the T-cell factor/lymphoid enhancing factor (TCF/LEF) family (TCFs) to repress WNT-β-catenin-dependent transcription without contacting DNA. Here, we show that ZIC activity at the neural plate border is influenced by WNT-dependent SUMOylation. In the presence of high canonical WNT activity, a lysine residue within the highly conserved zinc finger N-terminally conserved (ZF-NC) domain of ZIC5 is SUMOylated, which reduces formation of the ZIC-TCF co-repressor complex and shifts the balance towards transcription factor function. The modification is crucial in vivo, as a ZIC5 SUMO-incompetent mouse strain exhibits neural crest specification defects. This work reveals the function of the ZF-NC domain within ZIC, provides in vivo validation of target protein SUMOylation and demonstrates that WNT-β-catenin signalling directs transcription at non-TCF DNA-binding sites. Furthermore, it can explain how WNT signals convert a broad region of Zic ectodermal expression into a restricted region of neural crest cell specification. [ABSTRACT FROM AUTHOR]

Zinc finger of the cerebellum (Zic) proteins act as classic transcription factors to promote transcription of the Foxd3 gene during neural crest cell specification. Additionally, they can act as co-factors that bind proteins from the T-cell factor/lymphoid enhancing factor (TCF/LEF) family (TCFs) to repress WNT-ß-catenin-dependent transcription without contacting DNA. Here, we show that ZIC activity at the neural plate border is influenced by WNT-dependent SUMOylation. In the presence of high canonical WNT activity, a lysine residue within the highly conserved zinc finger N-terminally conserved (ZF-NC) domain of ZIC5 is SUMOylated, which reduces formation of the ZIC-TCF co-repressor complex and shifts the balance towards transcription factor function. The modification is crucial in vivo, as a ZIC5 SUMO-incompetent mouse strain exhibits neural crest specification defects. This work reveals the function of the ZF-NC domain within ZIC, provides in vivo validation of target protein SUMOylation and demonstrates that WNT-ß-catenin signalling directs transcription at non-TCF DNA-binding sites. Furthermore, it can explain how WNT signals convert a broad region of Zic ectodermal expression into a restricted region of neural crest cell specification. [ABSTRACT FROM AUTHOR]

Background: Anemia during childhood adversely affects mental, physical and social development of the children. This study is aimed to assess the prevalence of anemia and its associated factors among children less than five years of age in Guguftu, South Wollo, Northeast Ethiopia. Method: A cross-sectional health facility based study was conducted among 404 children aged 6 to 59 months. Systematic random sampling technique was used to include the participants. Pretested and structured questionnaires were used to collect socioeconomic and demographic characteristics of the family and child. Data on nutritional status, capillary blood and stool samples were collected from each child. Multivariate logistic regression was used to calculate adjusted odds ratios and the corresponding 95% confidence intervals. Result: The overall prevalence of anemia was 41.1% (95% CI;36.6% - 45.8%). Of the anemic under five children, 112 (67.5%) had mild anemia, 52(31.3%) had moderate anemia, and 2(1.2%) had severe anemia. Children who were in the age group of 6–11(AOR = 4.52; 95% CI: 1.67–12.34) and 12–23 (AOR = 2.79; 95% CI: 1.04–7.51) months, living in an urban (AOR = 1.83; 95% CI: 1.05–3.18), with no formal education mothers (AOR = 7.05; 95% CI: 2.93–17.01) and primary education mothers (AOR = 3.26; 95% CI: 1.29–8.24), with a family monthly income of <750 ETB(AOR = 5.19; 95% CI: 1.24–21.75) and 750–1500 ETB(AOR = 5.89; 95% CI: 1.45–23.98), with early (<6 months) introduction of complementary foods (AOR = 3.53; 95% CI: 1.23–10.18), Underweight (AOR = 2.11; 95% CI: 1.21–3.69) were more likely to become anemic. Conclusion: This study has revealed that the prevalence of anemia in children less than five years is high and a severe public health problem in the study area. Therefore, the policymakers should make a strategy that can reduce poverty and increase the awareness of women on breastfeeding, nutrition, and other associated factors to reduce anemia. [ABSTRACT FROM AUTHOR]

N-WASP is a major cytoskeletal regulator that stimulates Arp2/3-mediated actin nucleation. Here, we identify a nucleation-independent pathway by which N-WASP regulates the cytoskeleton and junctional integrity at the epithelial zonula adherens. N-WASP is a junctional protein whose depletion decreased junctional F-actin content and organization. However, N-WASP (also known as WASL) RNAi did not affect junctional actin nucleation, dominantly mediated by Arp2/3. Furthermore, the junctional effect of N-WASP RNAi was rescued by an N-WASP mutant that cannot directly activate Arp2/3. Instead, N-WASP stabilized newly formed actin filaments and facilitated their incorporation into apical rings at the zonula adherens. A major physiological effect of N-WASP at the zonula adherens thus occurs through a non-canonical pathway that is distinct from its capacity to activate Arp2/3. Indeed, the junctional impact of N-WASP was mediated by the WIP-family protein, WIRE, which binds to the N-WASP WH1 domain. We conclude that N-WASP-WIRE serves as an integrator that couples actin nucleation with the subsequent steps of filament stabilization and organization necessary for zonula adherens integrity. [ABSTRACT FROM AUTHOR]

Cadherin cell adhesion molecules are major determinants of tissue patterning which function in cooperation with the actin cytoskeleton . In the context of stable adhesion , cadherin/catenin complexes are often envisaged to passively scaffold onto cortical actin filaments. However, cadherins also form dynamic adhesive contacts during wound healing and morphogenesis . Here actin polymerization has been proposed to drive cell surfaces together , although F-actin reorganization also occurs as cell contacts mature . The interaction between cadherins and actin is therefore likely to depend on the functional state of adhesion. We sought to analyze the relationship between cadherin homophilic binding and cytoskeletal activity during early cadherin adhesive contacts. Dissecting the specific effect of cadherin ligation alone on actin regulation is difficult in native cell-cell contacts, due to the range of juxtacrine signals that can arise when two cell surfaces adhere . We therefore activated homophilic ligation using a specific functional recombinant protein. We report the first evidence that E-cadherin associates with the Arp2/3 complex actin nucleator and demonstrate that cadherin binding can exert an active, instructive influence on cells to mark sites for actin assembly at the cell surface. [Copyright &y& Elsevier]

Classic cadherins function as adhesion-activated cell signaling receptors. On adhesive ligation, cadherins induce signaling cascades leading to actin cytoskeletal reorganization that is imperative for cadherin function. In particular, cadherin ligation activates actin assembly by the actin-related protein (Arp)2/3 complex, a process that critically affects the ability of cells to form and extend cadherin-based contacts. However, the signaling pathway(s) that activate Arp2/3 downstream of cadherin adhesion remain poorly understood. In this report we focused on the Rho family GTPases Rae and Cdc42, which can signal to Arp2/3. We found that homophilic engagement of E-cadherin simultaneously activates both Rac1 and Cdc42. However, by comparing the impact of dominant-negative Rac1 and Cdc42 mutants, we show that Rac1 is the dominant regulator of cadherin-directed actin assembly and homophilic contact formation. To pursue upstream elements of the Rac1 signaling path- way, we focused on the potential contribution of Tiam1 to cadherin-activated Rae signaling. We found that Tiam1 or the closely-related Tiam2/STEF1 was recruited to cell-cell contacts in an E-cadherin-dependent fashion. Moreover, a dominant-negative Tiam1 mutant perturbed cell spreading on cadherin-coated substrata. However, disruption of Tiam1 activity with dominant-negative mutants or RNA interference did not affect the ability of E-cadherin ligation to activate Rac1. We conclude that Rac1 critically influences cadherin-directed actin assembly as part of a signaling pathway independent of Tiam1. [ABSTRACT FROM AUTHOR]

Classical cadherin adhesion molecules are key determinants of cell-cell recognition during development and in post-embryonic life. A decisive step in productive cadherin-based recognition is the conversion of nascent adhesions into stable zones of contact. It is increasingly clear that such contact zone extension entails active cooperation between cadherin adhesion and the force-generating capacity of the actin cytoskeleton. Cortactin has recently emerged as an important regulator of actin dynamics in several forms of cell motility. We now report that cortactin is recruited to cell-cell adhesive contacts in response to homophilic cadherin ligation. Notably, cortactin accumulates preferentially, with Arp2/3, at cell margins where adhesive contacts are being extended. Recruitment of cortactin is accompanied by a ligation-dependent biochemical interaction between cortactin and the cadherin adhesive complex. Inhibition of cortactin activity in cells blocked Arp2/3-dependent actin assembly at cadherin adhesive contacts, significantly reduced cadherin adhesive contact zone extension, and perturbed both cell morphology and junctional accumulation of cadherins in polarized epithelia. Together, our findings identify a necessary role for cortactin in the cadherin-actin cooperation that supports productive contact formation. [ABSTRACT FROM AUTHOR]