河流型水牛TGF-β基因家族鉴定及其胚胎发育早期的表达分析

Identification of TGF-βGene Family and Expression Analysisin Preimplantation Embryo Development of River Buffalo

本研究旨在鉴定河流型水牛中转化生长因子-β(transforming growth factor-β,TGF-β)基因家族成员,分析该家族成员在胚胎发育早期的表达情况,并讨论其可能的作用。根据人类中已鉴定的TGF-β基因家族信息,通过BLASTP在河流型水牛全基因组层面鉴定TGF-β家族成员,同时对牛、山羊和小鼠的TGF-β家族信息进行鉴定,结合5个物种中的TGF-β基因家族信息构建系统进化树。根据河流型水牛胚胎发育早期4个阶段(2-细胞、8-细胞、桑椹胚和囊胚期)的RNA-seq数据分析,通过FPKM(Fragment of Per Kilobase of exon model per Million mapped reads)值计算TGF-β家族成员的表达情况。结果显示,根据人类中的33个TGF-β基因,分别在河流型水牛、牛、山羊和小鼠的基因组中鉴定出32、23、32和26个TGF-β基因,几个物种中TGF-β基因家族成员数量相近且在系统进化树中分布均匀,说明该家族在各个物种中具有分布和功能的保守性。在河流型水牛的32个TGF-β基因中,21个TGF-β基因家族成员在胚胎发育早期不表达或极低剂量表达,6个分化抑制因子低剂量表达,5个高表达的TGF-β基因均有报道过与繁殖过程相关,说明在河流型水牛的胚胎发育早期只有部分成员(5/32)参与其中行使功能,绝大多数的TGF-β基因(27/32)并没有参与其中。本研究结果为河流型水牛中TGF-β基因家族研究提供了数据基础,并为TGF-β基因家族在胚胎发育早期的功能研究提供了理论依据。

This study was aimed to identify the transforming growth factor-β(TGF-β)gene family in River buffalo,detect their expression profiling,and analyze the possible function of TGF-βgene in preimplantation embryo development.According to the reported TGF-βgene in human,TGF-βfamily members in River buffalo were identified at the whole genome level by BLASTP,the TGF-βgene information in Bos taurus,Capra hircus and Mus musculus were characterized.Phylogenetic tree of TGF-βgene family was constructed to elucidate evolutional relationship among these five species.The expression of TGF-βgene was calculated by Fragment of Per Kilobase of exon model per Million mapped reads(FPKM)based on RNA-seq data at four stages of preimplantation embryo development(2-cell,8-cell,morula and blastocyst).The results showed that there were 32,23,32 and 26 TGF-βgene in River buffalo,Bos taurus,Capra hircus and Mus musculus,respectively.The similar numbers of TGF-βgene among five species and uniform distribution in the phylogenetic tree indicated that the conservation of TGF-βgene distribution and function among different species.In 32 TGF-βgene of River buffalo,21 TGF-βgene did not express(or extremely low express)in preimplantation embryo development,6 TGF-βgene which had been identified as inhibitor,exhibited low expression level.5 TGF-βgene,which were involved in reproduction,showed high expression level,which suggested that only partial of TGF-βgene(5/32)rather than most of them(27/32)were involved in preimplantation embryo development of River buffalo.The results provided the foundation for the study of TGF-βgene family in River buffalo,and provided a theoretical basis for the functional analysis of TGF-βgene family in early embryonic development.