Proteomic analysis of skin tissue under different colors of wool of Capra hircus

【Objective】To carry out proteomic analysis of black and white wool color difference in Capra hircus, and to identify the specific proteins and their pathways that influenced the wool difference, so as to provide reference for revealing the mechanism of characteristic wool color of C. hircus.【Method】The back skin tissue under black wool and the abdomen skin tissue under white wool of 3 male C. hircus were detected and extracted using SDT cleavage method and analyzed quantitatively, and then significantly differential proteins were analyzed by GO function annotation, KEGG pathway enrichment and subcellular localization, respectively.【Result】By comparison, 420 differentially expressed proteins which mainly involved in biological processes, molecular functions and cell components were screened in this study. Compared with the white wool control group, 247 of the 420 significantly differential proteins in the black wool test group were up-regulated while 173 were down-regulated. Fifteen differentially expressed proteins related to melanogenesis in black wool were screened, including 9 up-regulated proteins such as epidermal retinol dehydrogenase 2(SDR16C5), retinol dehydrogenase 16(RDH16), keratin 79(KRT79), etc. and 6 down-regulated proteins such as protein kinase B (AKT), secreted frizzled related protein 1(SFRP1), etc. The results of GO function annotation analysis showed that these significantly differential proteins were annotated on 51 GO functional items of biological process, molecular function and cell component. Subcellular localization analysis showed that 159 proteins were located in cytoplasm, 128 in nucleus and 88 in mitochondria, respectively. The enrichment analysis of KEGG pathway showed that these significantly differential proteins were enriched in 209 KEGG pathways, of which 5 signal pathways were related to retinol metabolism, melanogenesis, MAPK, PI3K-Akt and Wnt/β-Catenin.【Conclusion】Reasons leading to the difference of black and white coat color in C. hircus are:For one, both the expression of KRT79 involved in the melanogenesis pathway and the expression of SDR16C5, RDH16 and RETSAT involve in the retinol pathway were up-regulated, which promotes the formation of melanin in melanocytes and the formation of black wool;for another, it is attributed to the down-regulation of AKT in PI3K-AKT pathway and the down-regulation of SFRP1 which would reduce the inhibition for Wnt/β-Catenin signaling pathway, and it is beneficial to melanin synthesis.