Project description:The Sex-linked orange mutation in domestic cats causes variegated patches of reddish/yellow hair and is a defining signature of random X-inactivation in female tortoiseshell and calico cats. Unlike the situation for most coat color genes, there is no apparent homolog for Sex-linked orange in other mammals. We show that Sex-linked orange is caused by a 5 kb deletion that leads to ectopic and melanocyte-specific expression of the Rho GTPase Activating Protein 36 (Arhgap36) gene. Single cell RNA-seq studies from fetal cat skin reveal that red/yellow hair color is caused by reduced expression of melanogenic genes that are normally activated by the Melanocortin 1 receptor (Mc1r)—cyclic adenosine monophosphate (cAMP)—protein kinase A (PKA) pathway, but Mc1r and its ability to stimulate cAMP accumulation is intact. Instead, we show that expression of Arhgap36 in melanocytes leads to reduced levels of the PKA catalytic subunit (PKAC); thus, Sex-linked orange is genetically and biochemically downstream of Mc1r. Our findings resolve a longstanding comparative genetic puzzle, provide in vivo evidence for the ability of Arhgap36 to inhibit PKA, and reveal a molecular explanation for a charismatic color pattern with a rich genetic history.
Project description:The Sex-linked orange mutation in domestic cats causes variegated patches of reddish/yellow hair and is a defining signature of random X-inactivation in female tortoiseshell and calico cats. Unlike the situation for most coat color genes, there is no apparent homolog for Sex-linked orange in other mammals. We show that Sex-linked orange is caused by a 5 kb deletion that leads to ectopic and melanocyte-specific expression of the Rho GTPase Activating Protein 36 (Arhgap36) gene. Single cell RNA-seq studies from fetal cat skin reveal that red/yellow hair color is caused by reduced expression of melanogenic genes that are normally activated by the Melanocortin 1 receptor (Mc1r)—cyclic adenosine monophosphate (cAMP)—protein kinase A (PKA) pathway, but Mc1r and its ability to stimulate cAMP accumulation is intact. Instead, we show that expression of Arhgap36 in melanocytes leads to reduced levels of the PKA catalytic subunit (PKAC); thus, Sex-linked orange is genetically and biochemically downstream of Mc1r. Our findings resolve a longstanding comparative genetic puzzle, provide in vivo evidence for the ability of Arhgap36 to inhibit PKA, and reveal a molecular explanation for a charismatic color pattern with a rich genetic history.
Project description:Coat color mainly reflects pigmentation resulting from melanin. Wool color is one of the most visible and heritable traits in sheep. Although several detailed molecular mechanisms involved in coat color have been elucidated, our understanding of differences in gene expression patterns of wool color-related genes in Chinese Merino (Junken type) is limited. We employed the Affymetrix microarray to identify differentially expressed genes. 122 genes were differentially expressed, consisting of 117 upregulated and 5 downregulated genes that were related to black/brown skin. The expression level of the BMP2, BMP4, TYRP1, LEPR, DCT, BMPR1A, and TP45A genes was validated by qRT-PCR, and the results coincided with those of microarray. The expression level of ASIP in the black/brown group was significantly lower than that of the white group, suggesting that this plays a key role in the regulation of wool pigmentation. Some cloned color genes (MITF, MC1R, GPR143, and KIT) showed no significant differences in expression levels between the black/brown- and white-skinned sheep. Functional annotation by using Gene Ontology (GO) showed that the differentially expressed genes enriched specific GO terms, particularly those relating to melanin biosynthesis and metabolic processes. KEGG pathway analysis indicated that the categories of tyrosine metabolism and melanogenesis pathway were enriched with differentially expressed genes. Taken together, the present study has shown that the tyrosine metabolism pathway plays an essential role in regulating wool color. The findings of this study may also be utilized in the elucidation of the molecular mechanisms and relationship between genes and wool color in Chinese Merino (Junken type). We used microarrays to detail the global programme of gene expression and identified distinct different expression genes of skin in different coat color Chinese Merino (Junken type).
Project description:Histone modifications and CTCF mark the locations of genomic regulatory regions -- including promoters, enhancers, and insulators -- and have not been previously annotated for the domestic cat genome. Understanding where non-coding sequence variants fall in relation to regulatory regions is vital for determining their impact on gene function and their ability to cause disease. The addition of replicated feline ChIP-seq data from multiple tissues will aid in interpretation of non-coding variants, furthering characterization of genetic diseases and genetic test development.
Project description:The domestic cat germinal vesicle (GV), which is physiologically similar to the human GV, gains the intrinsic ability to resume meiosis and support early embryo development during the pre-antral-to-antral follicle transition. However, little is known about nuclear proteins that contribute to this developmental process. We performed proteomic analysis of GVs identified candidate proteins for oocyte competence acquisition.
Project description:The inherent diversity of canines is closely intertwined with the unique color patterns of each dog population. These variations in color patterns are believed to have originated through mutations and selective breeding practices that occurred during and after the domestication of dogs from wolves. To address the significant gaps that persist in comprehending the evolutionary processes that underlie the development of these patterns, we generated and analyzed deep-sequenced genomes of 113 Korean indigenous Jindo dogs that represent five distinct color patterns to identify the associated mutations in CBD103, ASIP, and MC1R. The degree of linkage disequilibrium and estimated allelic ages consistently indicate that the black-and-tan dogs descend from the first major founding population on Jindo island, compatible with the documented literature. We additionally demonstrate that black-and-tan dogs, in contrast to other color variations within the breed, exhibit a closer genetic affinity to ancient wolves from western Eurasia than those from eastern Eurasia. Lastly, population-specific genetic variants with moderate effects were identified, particularly in loci associated with traits underlying body size and behavioral variations, potentially explaining the observed phenotypic diversity based on coat colors. Overall, comparisons of whole genome sequences of each coat color population diverged from the same breed provided an unprecedented glimpse into the properties of evolutionary processes maintaining variation in Korean Jindo dog populations that were previously inaccessible.
Project description:Sperm maturation depends on exposure to specific microenvironments within the different segments of the epididymis, but mechanisms underlying how these microenvironments are produced or maintained are not well understood. We hypothesize that epididymal extracellular vesicles (EVs) could play a role in this process, and therefore set out to test whether the EVs from different regions of the epididymis can serve as a form of paracrine communication between epithelial cells. Domestic cat tissues were used to develop a reproducible in vitro culture system for corpus epididymis explants that were then exposed to EVs collected from upstream (i.e., caput) segments. The impacts of different culture or exposure conditions were compared by analyzing the morphology, apoptosis, transcriptional activity, and gene expression in the explants. Here, we report the development of the first in vitro culture system for epididymal tissue explants in the domestic cat model. Using this system, we found that EVs from the caput segment have a significant effect on the transcriptional profile of tissue from the corpus segment (1,233 differentially expressed genes due to EV supplementation). Of note, expression of genes associated with regulation of epithelial cell differentiation and cytokine signaling in the epididymis were regulated by the presence of EVs. Together, our findings comprise the first report of paracrine control of segmental gene regulation by epididymal EVs in any species. These results contribute to a better understanding of epididymis biology and could lead to techniques to enhance or suppress male fertility.