文昌鱼SMYD家族基因的系统进化分析

Phylogenetic Analysis of the Amphioxus SMYD Gene Family

SMYD(SET and MYND domain containing,SMYD)是一类含有SET功能域的蛋白,在染色体的调节、基因的表达、细胞生长周期的控制、细胞的分裂、分化及发育等方面具有重要作用.目前已知在果蝇、脊椎动物中均含有Smyd基因,且这些基因的进化、表达及功能均有很多研究,但关于脊索动物SMYD家族基因的研究则很少.本文对头索动物文昌鱼的基因组进行搜索,发现文昌鱼有6个可能的Smyd基因.对Smyd基因在染色体上的位置分析结果显示:文昌鱼Smyd相关基因同其他已经研究过的物种如爪蟾、小鼠、人等一样,均是散在分布于不同的染色体上.对这些基因的功能域的分析结果显示:文昌鱼的3个Smyd基因,斑马鱼的2个Smyd基因和人的4个Smyd基因除了含有SET功能域之外,还有另外一个SCOP功能域.基因结构的分析表明:脊椎动物的基因结构比较保守,但无脊椎动物及脊索动物的基因结构则保守性较差.而系统进化分析的结果则显示,文昌鱼Smyd相关的6个基因中只有两个与其他物种同源性较高,其余四个则相对较低.本文旨在对文昌鱼SMYD家族基因进行初步的系统进化分析,但脊索动物文昌鱼的Smyd基因在体内到底执行什么样的功能,其功能又是如何实现的,都有待于进一步研究.

SMYD （ SET and MYND domain containing, SMYD） are a class of proteins containing the SET func-tional domains. They play an important role in the regulation of chromosomal gene expression, cell cycle con-trol, cell division, differentiation and development. It is known that drosophila and vertebrates contain Smydgenes and scholars have done much research on the expression, function and evolution of these genes. Howev-er, research on the chordate SMYD family genes is limited. This article searched the cephalochordateamphioxus genome and found that amphioxus had six possible Smyd genes. Analysis of the functional domainsof these Smyd genes showed that ： amphioxus-related genes and those of other studied species, such as drosophi-la,xenopus, mouse, human are alike, all in different chromosomes. Analysis of gene structures shows that 3Smyd genes of the amphioxus,2 of zebrafish and 4 of human have a SCOP functional domain in addition to theSET functional domains. Analysis of gene structure show that the genetic structure of vertebrates is conserva-tive, but invertebrates and chordata are less conservative. The results of phylogenetic analysis show that onlytwo of the six arnphioxus Smyd genes are high homologous with other species and the other four are relativelylow. This paper aims to conduct a preliminary phylogenetic analysis of amphioxus SMYD family. What roles theSmyd genes in chordate amphioxus perform, and how they realize their functions still need further studies.