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The Nova Scotia Duck Tolling Retriever (NSDTR) is predisposed to immune mediated rheumatic disease (IMRD), steroid-responsive meningitis-arteritis (SRMA) and certain forms of cancer. Cytokines are the main regulators of the immune system. Interleukin 2 is a cytokine involved in activation of T regulatory cells, playing a role in central tolerance and tumor immunity. Interleukin 12 and interleukin 23 share the same subunit, p40, and are both pro-inflammatory cytokines. The aim of this study was to compare levels of IL-2 in healthy NSDTRs to those with cancer or autoimmune disease and to compare levels of IL-12/IL-23p40 in healthy NSDTRs and beagles versus NSDTRs with cancer or autoimmune disease. 62 dogs were included in the analysis of IL-12/IL-23p40; healthy NSDTRs (n = 16), healthy beagles (n = 16), NSDTRs autoimmune (n = 18) and NDSTRs lymphoma/mastocytoma (n = 12) and 68 dogs for IL-2; healthy (n = 20), autoimmune (n = 36) and lymphoma/mastocytoma/adenocarcinoma (n = 12). NSDTRs with autoimmune disease had higher levels of IL-12/IL-23p40 compared to healthy dogs (p = 0.008). NSDTRs with lymphoma also had higher levels of IL-12/IL-23p40 compared to healthy NSDTRs (p = 0.002). There was no difference in levels of IL-2 between healthy and diseased NSDTR. Statistical analysis was performed using Bonferroni corrections for multiple testing. These findings can contribute to the knowledge of autoimmune disease and cancer in dogs. [ABSTRACT FROM AUTHOR]

Pyometra is one of the most common diseases in female dogs, presenting as purulent inflammation and bacterial infection of the uterus. On average 20% of intact female dogs are affected before 10 years of age, a proportion that varies greatly between breeds (3–66%). The clear breed predisposition suggests that genetic risk factors are involved in disease development. To identify genetic risk factors associated with the disease, we performed a genome-wide association study (GWAS) in golden retrievers, a breed with increased risk of developing pyometra (risk ratio: 3.3). We applied a mixed model approach comparing 98 cases, and 96 healthy controls and identified an associated locus on chromosome 22 (p = 1.2 × 10–6, passing Bonferroni corrected significance). This locus contained five significantly associated SNPs positioned within introns of the ATP-binding cassette transporter 4 (ABCC4) gene. This gene encodes a transmembrane transporter that is important for prostaglandin transport. Next generation sequencing and genotyping of cases and controls subsequently identified four missense SNPs within the ABCC4 gene. One missense SNP at chr22:45,893,198 (p.Met787Val) showed complete linkage disequilibrium with the associated GWAS SNPs suggesting a potential role in disease development. Another locus on chromosome 18 overlapping the TESMIN gene, is also potentially implicated in the development of the disease. [ABSTRACT FROM AUTHOR]

Tartrate-resistant acid phosphatase type 5 (TRAP) exists as two isoforms, 5a and 5b. 5b is a marker of osteoclast number and 5a of chronic inflammation; however, its association with bone resorption is unknown. In this study, a double-TRAP 5a/5b sandwich ELISA measuring 5a and 5b protein in the same sample was developed. TRAP 5a and 5b protein levels were evaluated as osteoclast differentiation/activity markers in serum and in culture, and their correlation to the resorption marker CTX-I was examined. Serum TRAP 5a and 5b concentrations in healthy men were 4.4 ± 0.6 ng/ml and 1.3 ± 0.2 ng/ml, respectively, and they correlated moderately to each other suggesting that their secretion is coupled under healthy conditions. A correlation was also observed between serum TRAP 5a and 5b with CTX-I, suggesting that both TRAP isoforms associate with osteoclast number. During osteoclast differentiation on plastic/bone, predominantly 5b increased in media/lysate from M-CSF/RANKL-stimulated CD14+ PBMCs. However, substantial levels of 5a were detected at later stages suggesting that both isoforms are secreted from differentiating OCs. More TRAP 5b was released on bone indicating a connection to osteoclast resorptive activity, and a peak in TRAP 5b/5a-ratio coincided with rapid CTX-I release. At the end of the culture period of M-CSF + RANKL-stimulated CD14+ PBMCs, there was a correlation between the secretion of TRAP 5a and 5b proteins with CTX-I. The correlation of not only 5b but also 5a with collagen degradation, both in serum and osteoclast cultures indicates that a considerable proportion of the TRAP 5a originates from osteoclasts and may reflect a hitherto undisclosed regulatory mechanism during bone resorption and bone remodeling. [ABSTRACT FROM AUTHOR]

Phosphorylated osteopontin (OPN) inhibits hydroxyapatite crystal formation and growth, and bone alkaline phosphatase (BALP) promotes extracellular mineralization via the release of inorganic phosphate from the mineralization inhibitor inorganic pyrophosphate (PPi). Tartrate-resistant acid phosphatase (TRAP), produced by osteoclasts, osteoblasts, and osteocytes, exhibits potent phosphatase activity towards OPN; however, its potential capacity as a regulator of mineralization has not previously been addressed. We compared the efficiency of BALP and TRAP towards the endogenous substrates for BALP, i.e., PPi and pyridoxal 5'-phosphate (PLP), and their impact on mineralization in vitro via dephosphorylation of bovine milk OPN. TRAP showed higher phosphatase activity towards phosphorylated OPN and PPi compared to BALP, whereas the activity of TRAP and BALP towards PLP was comparable. Bovine milk OPN could be completely dephosphorylated by TRAP, liberating all its 28 phosphates, whereas BALP dephosphorylated at most 10 phosphates. OPN, dephosphorylated by either BALP or TRAP, showed a partially or completely attenuated phosphorylation-dependent inhibitory capacity, respectively, compared to native OPN on the formation of mineralized nodules. Thus, there are phosphorylations in OPN important for inhibition of mineralization that are removed by TRAP but not by BALP. In conclusion, our data indicate that both BALP and TRAP can alleviate the inhibitory effect of OPN on mineralization, suggesting a potential role for TRAP in skeletal mineralization. Further studies are warranted to explore the possible physiological relevance of TRAP in bone mineralization. [ABSTRACT FROM AUTHOR]

Canine atopic dermatitis is an inflammatory skin disease with clinical similarities to human atopic dermatitis. Several dog breeds are at increased risk for developing this disease but previous genetic associations are poorly defined. To identify additional genetic risk factors for canine atopic dermatitis, we here apply a Bayesian mixture model adapted for mapping complex traits and a cross-population extended haplotype test to search for disease-associated loci and selective sweeps in four dog breeds at risk for atopic dermatitis. We define 15 associated loci and eight candidate regions under selection by comparing cases with controls. One associated locus is syntenic to the major genetic risk locus (Filaggrin locus) in human atopic dermatitis. One selection signal in common type Labrador retriever cases positions across the TBC1D1 gene (body weight) and one signal of selection in working type German shepherd controls overlaps the LRP1B gene (brain), near the KYNU gene (psoriasis). In conclusion, we identify candidate genes, including genes belonging to the same biological pathways across multiple loci, with potential relevance to the pathogenesis of canine atopic dermatitis. The results show genetic similarities between dog and human atopic dermatitis, and future across-species genetic comparisons are hereby further motivated.A genome-wide evaluation in four different dog breeds identifies multiple genomic regions that were significantly related to risk of atopic dermatitis, providing additional biological insights into disease pathogenesis in dogs. [ABSTRACT FROM AUTHOR]

Primary frequency control, also known as primary frequency response or droop, is one of the essential ancillary services guaranteeing stable operation of any power system. Provision of primary and secondary frequency control reserves creates high costs to the system operator. Demand Response, that is an automatic contribution by flexible loads, may provide some of the reserves needed for grid operation at lower cost than traditional power plants. An improved algorithm for primary frequency control provision with refrigerators is described. This algorithm (1) prevents synchronization of participating loads, and (2) guarantees continuous frequency support. A simulation based on a dynamic two-area system resembling the central European grid shows the performance of the algorithm, compliance with refrigerator temperature limits and improvements in power system frequency response after a contingency. [ABSTRACT FROM AUTHOR]

Tartrate-resistant acid phosphatase (TRAP) is known as an osteoclast marker, but osteoblasts and osteocytes in the vicinity of bone remodeling sites also express TRAP. Cell culture studies suggest that osteoblasts endocytose osteoclastic TRAP for inactivation. To evaluate whether changes in osteoclast activity could alter TRAP expression in osteoblasts and/or osteocytes in vivo, we studied the ovariectomized and vitamin D-deficient rat (Ovx-D) and rats healing from rickets. Bone sections were analyzed for TRAP gene expression by in situ hybridization, TRAP protein by immunogold labeling, and TRAP enzyme activity using the fluorescent substrate ELF97. Osteoblasts and osteocytes close to intracortical remodeling sites and bone surfaces demonstrated TRAP, most prominently in cancellous bone and osteocytes. Intracellular TRAP was located to electron-dense vesicles with similar morphology in both cell types. Ovx-D increased osteoclast activity ( p < 0.001) and ELF97 osteocytes ( p < 0.05) in cancellous bone, but no corresponding increase was observed in the osteocyte lacunar area. The level of TRAP vesicles in cortical osteoblasts ( p < 0.01) in Ovx-D rats was also increased. Enhanced osteoclast activity was noted in healing rickets after 72 h ( p < 0.05), but no differences in TRAP expression were detected in osteoblasts or osteocytes. Thus, increased osteoclast activity does not affect TRAP expression in osteoblasts and osteocytes, favoring the notion that increased TRAP in these cells is rather due to increased synthesis. Although the role of TRAP in osteoblasts and osteocytes remains elusive, we speculate that the function is related to the capability of the enzyme to regulate the phosphorylation of proteins known to be expressed by these cells. [ABSTRACT FROM AUTHOR]

The purpose of this study was to explore whether mechanical loading by exercise over a 1-year period in postmenopausal women had an effect on the receptor activator for nuclear factor kappa B ligand/osteoprotegerin (RANKL/OPG) system or the levels of the Wnt-signaling antagonist sclerostin. A total of 112 postmenopausal were randomized to either sedentary life (controls) or physical activity (training group). Ninety-two women fulfilled the study protocol. The training program consisted of three fast 30-min walks and one or two 1-h aerobic training sessions per week. The effect on the bone mineral density of the hip assessed with dual X-ray absorptiometry was positive as reported earlier. Blood samples were taken from participants at baseline and after 1 year and serum levels of OPG, RANKL and sclerostin were quantified together with the bone metabolism markers C-terminal telopeptide of collagen type I (CTX) and bone-specific alkaline phosphatase (BALP). The results were analyzed using an analysis of covariance model using baseline values as the covariate. The training group displayed a clear mean increase of OPG +7.55 pg/ml compared to controls ( p = 0.007). The mean changes for RANKL +0.19 pg/ml (square-root transformed data) and sclerostin +0.62 pmol/l were non-significant ( p = 0.13 and p = 0.34). The changes in bone turnover markers CTX and BALP showed a tendency to decrease in the training group versus controls but the changes were small and non-significant. Although our study is limited in number of participating women, we have been able to show an OPG-associated, and RANKL- and sclerostin-independent, training-induced inhibition of postmenopausal bone loss. [ABSTRACT FROM AUTHOR]

Vitamin A is the only known compound that produces spontaneous fractures in rats. In an effort to resolve the molecular mechanism behind this effect, we fed young male rats high doses of vitamin A and performed microarray analysis of diaphyseal bone with and without marrow after 1 week, i.e., just before the first fractures appeared. Of the differentially expressed genes in cortical bone, including marrow, 98% were upregulated. In contrast, hypervitaminotic cortical bone without marrow showed reduced expression of 37% of differentially expressed genes. Gene ontology (GO) analysis revealed that only samples containing bone marrow were associated with a GO term, which principally represented extracellular matrix. This is consistent with the histological findings of increased endosteal/marrow osteoblast number. Fourteen genes, including Cyp26b1, which is known to be upregulated by vitamin A, were selected and verified by real-time PCR. In addition, immunohistochemical staining of bone sections confirmed that the bone-specific molecule osteoadherin was upregulated. Further analysis of the major gene-expression changes revealed apparent augmented Wnt signaling in the sample containing bone marrow but reduced Wnt signaling in cortical bone. Moreover, induced expression of hypoxia-associated genes was found only in samples containing bone marrow. Together, these results highlight the importance of compartment-specific analysis of bone and corroborate previous observations of compartment-specific effects of vitamin A, with reduced activity in cortical bone but increased activity in the endosteal/marrow compartment. We specifically identify potential key osteoblast-, Wnt signaling-, and hypoxia-associated genes in the processes leading to spontaneous fractures. [ABSTRACT FROM AUTHOR]

The serum protein prothrombin (PT) is proteolytically converted to thrombin during the coagulation cascade by the cell-associated prothrombinase complex. In vitro, RANKL-differentiated osteoclasts express tissue factor and coagulation factor Xa, which convert PT to thrombin (Karlstrom et al. Biochem Biophys Res Commun 394:593-599, ). The present study investigated the localization of PT in bone as well as the expression of PT mRNA in bone and osteoclasts. Herein, immunoblot analysis detected PT and smaller proteolytically cleaved fragments with sizes consistent with the action of prothrombinase in a protein fraction extracted with guanidine-HCl EDTA from mouse tibia. Light microscopic and ultrastructural immunohistochemistry demonstrated the presence of PT in the newly formed bone matrix of the metaphysis. Furthermore, fluorescent immunohistochemistry on metaphyseal trabecular bone showed that PT colocalized with MMP-9-expressing subepiphyseal osteoclasts, whereas cathepsin K-expressing osteoclasts were closely associated with PT of the bone matrix. RT-qPCR analysis revealed that PT mRNA was detected in tibia. Expression of PT mRNA in the tibia was 0.2% of the level in the liver. In addition, PT mRNA expression was increased by RANKL-induced differentiation of bone marrow macrophages to osteoclasts. The results demonstrate that PT is synthesized and proteolytically processed in bone. Furthermore, PT is present mainly in the newly formed bone matrix of the metaphyseal trabecular bone compartment in close association to osteoclasts. In addition, MMP-9-positive osteoclasts contain PT, and PT expression is increased during osteoclastogenesis. [ABSTRACT FROM AUTHOR]

Tartrate-resistant acid phosphatase (TRAP) exists in human serum as two major isoforms, monomeric 5a and proteolytically processed enzymatically active 5b. The 5b isoform is secreted by osteoclasts and has recently been advocated as a serum marker for bone metastasis in breast cancer patients. The 5a isoform, on the other hand, is not bone-derived and has been proposed to be a marker of activated macrophages and chronic inflammation. In this study, expression of TRAP protein and enzymatic activity in bone metastases from different primary sites was examined. TRAP activity was high in bone metastases from prostate cancer, intermediate in breast cancer, and low in lung and kidney cancers. The partially purified TRAP from breast cancer bone metastasis samples exhibited the enzymatic characteristics of purple acid phosphatase. Both 5a and 5b isoforms were expressed in bone metastases of different histogenetic origins, i.e. prostate, breast, lung and kidney, and also a novel previously unreported 42 kDa variant of the TRAP 5a isoform was identified in bone metastases. This novel TRAP 5a isoform was absent in human bone, indicating that the 42 kDa variant is specific to metastatic cancer tissue. Immunohistochemistry revealed that metastatic cancer cells were the predominant source of TRAP 5a, whereas tumor-associated macrophages and occasionally multinucleated giant cells in the tumor stroma preferentially expressed the proteolytically processed TRAP 5b variant. Our results indicate the presence of a previously unstudied variant of monomeric TRAP 5a in cancer cells, which may have functional and diagnostic implications. Moreover, the presence of TRAP-positive macrophages in bone metastases could, together with cancer cells and osteoclasts, contribute to the elevated levels of serum TRAP activity observed in patients with bone metastases. [ABSTRACT FROM AUTHOR]

The unique canine breed structure makes dogs an excellent model for studying genetic diseases. Within a dog breed, linkage disequilibrium is extensive, enabling genome-wide association (GWA) with only around 15,000 SNPs and fewer individuals than in human studies. Incidences of specific diseases are elevated in different breeds, indicating that a few genetic risk factors might have accumulated through drift or selective breeding. In this study, a GWA study with 81 affected dogs (cases) and 57 controls from the Nova Scotia duck tolling retriever breed identified five loci associated with a canine systemic lupus erythematosus (SLE)–related disease complex that includes both antinuclear antibody (ANA)–positive immune-mediated rheumatic disease (IMRD) and steroid-responsive meningitis-arteritis (SRMA). Fine mapping with twice as many dogs validated these loci. Our results indicate that the homogeneity of strong genetic risk factors within dog breeds allows multigenic disorders to be mapped with fewer than 100 cases and 100 controls, making dogs an excellent model in which to identify pathways involved in human complex diseases. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the cellular and molecular expression of tartrate resistant acid phosphatase (TRAP) as a marker of activated macrophages in macrophage dependent dextran sulphate sodium (DSS)-induced colitis in rats. In normal colon, TRAP+/CX3CR1+ macrophages were located in the upper part of the lamina propria. In the early stage (day 1–3) of acute colitis prior to histopathological changes, induction of the cytokines TNFα, IL-12 and IFNγ occurred concomitant with increased mRNA and enzyme activity of TRAP along with a slight increase of TRAP immunolabelling in macrophages of the upper lamina propria, suggesting induction of TRAP in resident macrophages. Among these cytokines, TNFα up-regulated TRAP expression in the RAW 264.7 monocyte/macrophage cell line. In a later phase (day 7) with fulminant colitis, a massive infiltration of macrophages including recruited TRAP+/CCR2+ cells was observed also in the lower part of the lamina propria as well as in the submuscular layer. Additionally, differentiated cellular expression of pro- and mature TRAP also suggest that mucosal macrophages in the lower part of lamina propria bordering the sub-mucosa provide a source of replenishment of macrophages situated in the upper lamina propria. In conclusion, induction of TRAP provides an early sign of macrophage responsiveness in DSS induced colitis. [ABSTRACT FROM AUTHOR]

Nova Scotia duck tolling retrievers are predisposed to a SLE-related disease complex including immune-mediated rheumatic disease (IMRD) and steroid-responsive meningitis–arteritis (SRMA). IMRD involves symptoms that resemble those seen in systemic autoimmune rheumatic diseases, such as systemic lupus erythematosus, SLE, or SLE-related diseases, in humans. This disease complex involves persistent lameness, stiffness, mainly after resting, and palpable pain from several joints of extremities. The majority of affected dogs display antinuclear autoantibody (ANA)-reactivity. SRMA is manifested in young dogs with high fever and neck stiffness and can be treated with corticosteroids. We have investigated the possible role of MHC class II as a genetic risk factor in IMRD and SRMA etiology. We performed sequence-based typing of the DLA-DRB1, -DQA1, and -DQB1 class II loci in a total of 176 dogs including 51 IMRD (33 ANA-positive), 49 SRMA cases, and 78 healthy controls (two dogs were both IMRD- and SRMA-affected). Homozygosity for the risk haplotype DRB1*00601/DQA1*005011/DQB1*02001 increased the risk for IMRD (OR = 4.9; ANA-positive IMRD: OR = 7.2) compared with all other genotypes. There was a general heterozygote advantage, homozygotes had OR = 4.4 (ANA-positive IMRD: OR = 8.9) compared with all heterozygotes. The risk haplotype contains the five amino acid epitope RARAA, known as the shared epitope for rheumatoid arthritis. No association was observed for SRMA. We conclude that DLA class II is a highly significant genetic risk factor for ANA-positive IMRD. The results indicate narrow diversity of DLA II haplotypes and identify an IMRD-related risk haplotype, which becomes highly significant in homozygous dogs. [ABSTRACT FROM AUTHOR]

With several hundred genetic diseases and an advantageous genome structure, dogs are ideal for mapping genes that cause disease. Here we report the development of a genotyping array with ∼27,000 SNPs and show that genome-wide association mapping of mendelian traits in dog breeds can be achieved with only ∼20 dogs. Specifically, we map two traits with mendelian inheritance: the major white spotting (S) locus and the hair ridge in Rhodesian ridgebacks. For both traits, we map the loci to discrete regions of <1 Mb. Fine-mapping of the S locus in two breeds refines the localization to a region of ∼100 kb contained within the pigmentation-related gene MITF. Complete sequencing of the white and solid haplotypes identifies candidate regulatory mutations in the melanocyte-specific promoter of MITF. Our results show that genome-wide association mapping within dog breeds, followed by fine-mapping across multiple breeds, will be highly efficient and generally applicable to trait mapping, providing insights into canine and human health. [ABSTRACT FROM AUTHOR]

The activation sequence of clasts (the designation clast was used because ultrastructurally in this tissue, it is not always possible to differentiate between chondroclasts sitting on cartilage and osteoclasts sitting on bone matrix) was studied in vivo using the healing of low-phosphate, vitamin D-deficiency rickets as a model system. Thus, the bones of 7-week-old rachitic animals were analyzed with a combination of morphological, biochemical, and molecular biological methods at 48 and 72 h, respectively, after change to normal food. A quantitative ultrastructural analysis showed that the number of clast profiles exhibiting the characteristic polarized features of actively resorbing cells, i.e., ruffled borders and clear zones, had reached normal levels after 48 h. By combining the data with quantitative analyses by the immunogold technique, we demonstrated that cathepsin K secretion was coupled to ruffled border formation in clasts irrespective of whether the number of polarized clasts was low (in rickets) or high (in healing). In contrast, the levels of tartrate-resistant acid phosphatase (TRAP) both between ruffles and in the outside matrix adjoining the ruffled border were low in polarized clasts both in rickets and at the early (48 h) healing time-point, but were increased at the latest (72 h) healing time-point. Interestingly, expression of TRAP and the cathepsin K at the mRNA level, as well as protein expression and the activity of TRAP, were not different during the healing sequence. Although the two enzymes are confined to the same clast populations, their secretion during the resorption process is apparently differentially regulated: cathepsin K secretion is coupled to ruffled border formation in clasts, whereas TRAP is secreted at a later stage during the resorption sequence, suggesting a role for secreted TRAP as a modulator of resorptive activity. [ABSTRACT FROM AUTHOR]

Most traits and disorders have a multifactorial background indicating that they are controlled by environmental factors as well as an unknown number of quantitative trait loci (QTLs). The identification of mutations underlying QTLs is a challenge because each locus explains only a fraction of the phenotypic variation. A paternally expressed QTL affecting muscle growth, fat deposition and size of the heart in pigs maps to the IGF2 (insulin-like growth factor 2) region. Here we show that this QTL is caused by a nucleotide substitution in intron 3 of IGF2. The mutation occurs in an evolutionarily conserved CpG island that is hypomethylated in skeletal muscle. The mutation abrogates in vitro interaction with a nuclear factor, probably a repressor, and pigs inheriting the mutation from their sire have a threefold increase in IGF2 messenger RNA expression in postnatal muscle. Our study establishes a causal relationship between a single-base-pair substitution in a non-coding region and a QTL effect. The result supports the long-held view that regulatory mutations are important for controlling phenotypic variation. [ABSTRACT FROM AUTHOR]

We investigated the relationship between flowering peaks of the mountain birch, Betula pubescens ssp. czerepanovii, and population levels of the autumnal moth Epirrita autumnata in Ammarnäs, Swedish Lapland, during 1968–2000, and in Budal, Central Norway, during 1972–2000. There was a significant correlation between the two moth series, both of which showed three well-defined population cycles during the study period. In both areas, the population growth index of the moth was negatively related to population size, but also to the number of years since the previous flowering peak of mountain birch. In the northern study area, Ammarnäs, there was an additional positive effect of the winter temperature index, probably due to increased mortality of moth eggs during cold winters. No significant relationships were found between the number of birch female catkins and larval density in the previous 2 years. Both in Ammarnäs and in an area without moth outbreaks in south-eastern Norway, birch flowering was positively related to temperatures during flower bud formation and to the number of years since the previous flowering peak. The results support the idea of a lower content of chemical defence compounds in birch leaves after a mast reproduction, though we cannot exclude the possibility that the negative relationship between flowering and moth population levels was influenced or caused by stress associated with defoliation during moth outbreaks. [ABSTRACT FROM AUTHOR]

HLA-DR haplotypes of the human major histocompatibility complex are organized in five different groups. They can be identified based on the serological specificity expressed by the polymorphic DRB1 locus and by the presence of a characteristic set of DRB genes. The nucleotide sequences of introns 4 and 5 of the two DRB genes ( DRB1 01 and DRB6 01) from a DR1 haplotype and the three DRB genes ( DRB1 15, DRB615, and DRB5 15), from a DR51 haplotype were determined. This study identified endogenous retrovial long terminal repeat elements ( ERV9 LTR) located at identical positions in intron 5 of the DRB1 genes in both the DR1 and DR51 haplotypes. Phylogenetic analyses revealed a close evolutionary relationship between these two haplotypes. The DRB5 gene, unique for the DR51 haplotype, may have been lost by a recent gene deletion event creating the DR1 haplotype. A model for the evolution of the human DR haplotypes involving separate duplication and contraction events is presented. [ABSTRACT FROM AUTHOR]

The HLA-DRB genes of the human major histocompatibility complex constitute a multigene family with a varying number of DRB genes in different haplotypes. To gain further knowledge concerning the evolutionary relationship, the complete nucleotide sequence was determined for a region spanning introns 4 and 5 of the three DRB genes ( DRB1*0301, DRB2 and DRB3*0101) from a DR52 haplotype and the single DRB gene ( DRB1*08021) in the DR8 haplotype. These analyses identified an endogenous retroviral long terminal repeat element ( ERV9 LTR3), inserted at identical positions in intron 5 of the functional DRB genes in these two haplotypes. Comparison of the nucleotide sequence from introns 4 and 5 including the ERV9 LTR elements revealed a strong similarity between the three expressed DRB genes. The DRB3*0101 and DRB1*08021 genes were most similar in this comparison. These findings provide further evidence for a separate duplication in a primordial DR52 haplotype followed by a gene contraction event in the DR8 haplotype. A homologous element was found in a chimpanzee DRB gene from a DR52 haplotype. This represents the first characterized ERV9 LTR element in a nonhuman species. The corresponding introns of the DRB genes in the DR4 haplotype contain no ERV9 LTRs. In contrast, these genes have insertions of distinct Alu repeats, implying distinct evolutionary histories of DR52 and DR53 haplotypes, respectively. Phylogenetic analyses of DRB introns from DR52, DR53, and DR8 haplotypes showed a close relationship between the DRB2 and DRB4 genes. Thus, the ancestral DR haplotype that evolved to generate the DR52 and DR53 haplotypes most likely shared a primordial common DRB gene. [ABSTRACT FROM AUTHOR]

In most individuals two HLA-DR genes are expressed from each chromosome. One of these genes encodes one of the classical DR specificities, while the other encodes either of the supertypic DRw52/DRw53 specificities. In addition to these genes usually one or two DR pseudogenes are present. In contrast, the DRw8 chromosomal region only contains a single DR gene. To determine the relationship of this single gene to the multiple DR genes of other DR specificities, comparisons of Southern genomic blots were carried out. In this analysis genomic clones for each individual DR chain locus were included. The DR w8 gene was indistinguishable from the DR III gene of DR3 cells (encoding DRw52), suggesting that it is closely related to the latter gene. The functional implications of this finding are discussed. [ABSTRACT FROM AUTHOR]

The dorsal hair ridge in Rhodesian and Thai Ridgeback dogs is caused by a dominant mutation that also predisposes to the congenital developmental disorder dermoid sinus. Here we show that the causative mutation is a 133-kb duplication involving three fibroblast growth factor (FGF) genes. FGFs play a crucial role in development, suggesting that the ridge and dermoid sinus are caused by dysregulation of one or more of the three FGF genes during development. [ABSTRACT FROM AUTHOR]

The mammalian Major Histocompatibility Complex (MHC) region contains several gene families characterized by highly polymorphic loci with extensive nucleotide diversity, copy number variation of paralogous genes, and long repetitive sequences. This structural complexity has made it difficult to construct a reliable reference sequence of the horse MHC region. In this study, we used long-read single molecule, real-time (SMRT) sequencing technology from Pacific Biosciences (PacBio) to sequence eight Bacterial Artificial Chromosome (BAC) clones spanning the horse MHC class II region. The final assembly resulted in a 1,165,328 bp continuous gap free sequence with 35 manually curated genomic loci of which 23 were considered to be functional and 12 to be pseudogenes. In comparison to the MHC class II region in other mammals, the corresponding region in horse shows extraordinary copy number variation and different relative location and directionality of the Eqca-DRB, -DQA, -DQB and -DOB loci. This is the first long-read sequence assembly of the horse MHC class II region with rigorous manual gene annotation, and it will serve as an important resource for association studies of immune-mediated equine diseases and for evolutionary analysis of genetic diversity in this region. [ABSTRACT FROM AUTHOR]