水牛STAT基因家族分析

STAT Gene Family Identification in Water Buffalo

试验通过生物信息学技术对信号转导和转录激活子(signal transducer and activators of transcription,STATs)基因家族进行了motif、基因结构分析、共线性分析、不同物种系统进化分析和表达量分析,旨在挖掘水牛STAT基因家族的功能。结果表明,水牛STAT基因家族共有7个家族成员并分别命名为bbu.STAT1~6,其中bbu.STAT5分为bbu.STAT5A和bbu.STAT5B。bbu.STAT1和bbu.STAT4位于2号染色体,bbu.STAT2和bbu.STAT6位于4号染色体,bbu.STAT3、bbu.STAT5A和bbu.STAT5B位于3号染色体。这7个STAT蛋白长度在748~865 aa之间,等电点PI均小于7,说明水牛STAT蛋白均属于酸性蛋白质。基因结构分析发现不同的组具有不同的内含子数模式。Motif分析发现,除bbu.STAT2外,均含有预测出的motif 1~10且排序相同,说明水牛STAT基因家族成员蛋白功能相似。共线性分析结果显示,水牛和奶牛中均存在3对相同成员的STAT基因表现出串联重复且没有发现片段重复,推测串联复制在水牛和奶牛STAT家族的扩增中起着主导作用。发现2个水牛STAT基因对的Ka/Ks值小于0.5,且STAT5A-STAT5B小于0.1,说明该基因对具有更强的纯化选择压力。不同物种STAT系统发育分析显示,STAT基因家族具有较高的保守性,其中水牛与奶牛和牦牛的聚类更为相近。表达量分析发现所有STAT基因在乳腺组织中均有表达,其中STAT5A的表达量最高,STAT4的表达量最低,推测水牛STAT基因家族参与调控乳房发育及泌乳过程,其中STAT5A可能起更重要的作用。

This study aims to perform the genomic identification, evolution, and expression analysis of the STAT gene family in water buffalo. The results showed that there were seven family members of STAT gene family in buffalo and named bbu and STAT1~6. STAT5 included bbu. STAT5 A and bbu. STAT5 B. bbu.STAT1 and bbu. STAT4 were located on chromosome 2, bbu. STAT2 and bbu. STAT6 were on chromosome 4. bbu. STAT3, bbu. STAT5 A and bbu.STAT5 B on chromosome 3. The length of these seven STAT proteins ranged from 748-865 aa, and the PI was all less than 7, indicating that buffalo STAT proteins were all acidic proteins. Genetic structure analysis revealed that different groups had different intron quantity patterns. Motif analysis showed that the predicted Motif 1-10 were found in all of them except for bbu. STAT2, and the sequence was the same, indicating that the functions of buffalo STAT gene family members were similar in buffalo and dairy cattle. The results of collinearity analysis showed that three buffalo STAT gene pairs were confirmed to be tandem duplicated genes, but no segmental duplication event was confirmed to be discovered. It was suggesting that tandem duplication had a predominant role in the expansion of buffalo and cattle STAT gene family. For the duplicated STAT pairs, we found that two pairs of duplicated STAT with the Ka/Ks ratios less than 0.5 were identified, one of them with the Ka/Ks ratios were less than 0.1, which might experience strong purifying selection pressure. The phylogenetic analysis showed that STAT gene family was highly conserved, and buffalo was more similar to cattle and yak. Expression analysis showed that all STAT genes expressed in mammary gland, and STAT5 A had the highest expression level, STAT4 had the lowest expression level. It was suggesting that the STAT gene family in buffalo affecting mammary gland development and lactation, and STAT5 A might play a more important role.