摘要
MKLN1基因编码的muskelin蛋白主要通过其羧基端的kelch重复结构域与其它蛋白形成复合物行使功能。通过分析草鱼鳃组织的基因转录谱,发现其中的MKLN1基因存在(CT)15的微卫星序列,通过检测3个不同的草鱼种群,又发现(CT)9、(CT)10、(CT)11和(CT)13 4种多态性序列。通过克隆该段MKLN1基因组序列并与斑马鱼和红鳍东方鲀的MKLN1基因组序列比较,发现克隆得到的草鱼基因序列是由一个内含子和两个外显子组成,共编码144个氨基酸。通过进一步调查不同组织该基因的转录本,发现存在内含子剪接和内含子未被剪接的两个转录本。由于内含子序列未被剪接的转录本在内含子中存在"TGA"终止密码子,导致MKLN1基因翻译提前终止,翻译产物为失去部分kelch结构域的muskelin蛋白。相对于内含子正常剪接的转录本,没有被剪接内含子的转录本在各种组织中的表达量要明显低得多。简而言之,本研究发现了草鱼MKLN1转录本中的微卫星序列是来自未被剪切的内含子,而未被剪切的内含子导致该转录本编码部分kelch结构域缺失的muskelin蛋白。研究亮点:目前对于可直接锚定功能基因的I型微卫星标记研究很少。本文首次发现MKLN1基因EST序列中的二核苷酸的微卫星是来自可变剪接导致的未被剪切掉的内含子,表明RNA可变剪接是造成ESTs序列中含微卫星序列的一种途径。
Muskelin coded by MKLN1 gene participates in signal transduction,cell-matrix adhesion and cellular component movement as an intracellular protein.In previous study,MKLN1 containing 15 repeats of dinucleotide（CT） was identified from a cDNA library of grass carp,Ctenopharyngodon idellus.To further investigate the polymorphism of the dinucleotide,we examined ten individuals from three different grass carp population in this research and identified other different repeats of dinucleotide as（CT）9,（CT）10,（CT）11 and（CT）13.Each individual owning at most two loci indicates only one copy MKLN1 in the genome of grass carp.Compared with its orthologure in zebrafish（Danio rerio） or fugu（Takifugu rubripes） genome,the dinucleotide microsatellite was found not in an exon,but in one intron corresponding 10th intron of MKLN1 in Danio rerio or Takifugu rubripes.Further investigation mRNA fragment spanning from 10th to 11th exons showed that there existed mRNA alternative splicing in MKLN1 and the microsatellite was indeed located in unspliced 10th intron in grass carp.Terminal code ＂TGA＂ locating in unspliced intron leads the transcript to translate into truncated muskelin.The truncated muskelin might lose partial function because of kelch domain broken.Moreover,the abundance of unspliced transcript was higher than that of spliced transcript in gill,intestine,head kidney,skin,hepatopancreas,muscle and kidney.Taken together,the microsatellite we found in one EST of MKLN1 is from an unspliced intron,and the unspliced intron leads the transcript to encode truncate muskelin.
出处
《上海海洋大学学报》
CAS
CSCD
北大核心
2011年第5期649-654,共6页
Journal of Shanghai Ocean University
基金
上海市教育委员会重点学科建设项目(S30701和J50701)
关键词
草鱼
MKLN1
微卫星多态性
可变剪接
Ctenopharyngodon idellus
MKLN1
polymorphic microsatellite
alternative splicing transcription
