TYRP1和MLANA影响朗德鹅羽色形成的机制研究

Involvement of TYRP1 and MLANA in Formation of Feather Color of Landes Goose

研究旨在确定羽色形成的关键候选基因,为筛查鹅羽色的控制基因提供有用信息。利用1月龄和2月龄灰、白羽朗德鹅皮肤样品(n=12),通过定量PCR测定MLANA、TYRP1、MC1R、ASIP和SLC45A2基因的m RNA表达量。从血细胞中提取基因组DNA,通过测序检测MLANA和TYRP1基因上游序列的核酸多态性。结果显示:在1月龄样品中,ASIP基因表达量在灰、白羽间无显著差异,而其他基因的表达量均存在显著差异(P<0.05),且白羽低于灰羽。2月龄时,MC1R和SLC45A2基因的表达量在羽色间无显著差异,但白羽中的ASIP基因表达量显著高于灰羽(P<0.05)。与1月龄相一致,白羽中MLANA和TYRP1的表达量均显著低于灰羽(P<0.05)。此外,MLANA和TYRP1的上游调控序列中并未发现核酸多态性。结果表明:MLANA和TYRP1基因所在的信号通路对鹅灰、白羽形成至关重要,白羽的TYRP1表达缺失可能受αMSH/MC1R分支以外的其他信号通路分支影响。

The purpose of this study was to determine the key candidate genes for the formation of feather color,and provide useful information for screening for the causative genes of feather color in goose. RNA was extracted from the skins of 1-and 2-month-age gray and white Lande geese（n=12）, and m RNA expression levels of MLANA,TYRP1, MC1 R, ASIP and SLC45 A2 genes were determined by quantitative PCR. Genomic DNA was extracted from the blood cells, and DNA polymorphisms in the upstream sequences of MLANA and TYRP1 genes was determined by sequencing analysis. The results showed that in the skins of 1-month-age gray-feather and white-feather Landes geese, the expression of ASIP gene was not significantly different between geese with different feather colors, whereas the expression of MC1 R, SLC45 A2, MLANA and TYRP1 genes were significantly different with lower expression level in the white-feather goose（P0.05）. In the skins of 2-month-age gray and white-feather Landes goose, there were no significant difference in the expression of MC1 R and SLC45 A2 between geese with gray and white feather color, whereas ASIP gene expression in white-feather goose was significantly higher than that in gray-feather goose（P〈0.05）. Moreover,consistent with the observations in the 1-month-age goose, the expression levels of MLANA and TYRP1 genes in the skins of white-feather goose were significantly lower than those of gray geese（P〈0.05）.In addition, nucleic acid polymorphic loci were not found in the upstream regulatory sequences of MLANA and TYRP1 genes. The results indicated that the signaling pathways in that MLANA and TYRP1 genes were involved were critical to the formation of goose feather color,and the absent expression of TYRP1 gene in the skins of white-feather goose was unlikely due to the influence ofαMSH/MC1 R branch but the other branches of signal pathway.