日本七鳃鳗(Lampetra japonica)口腔腺表达序列标签(EST)分析

以日本七鳃鳗口腔腺为材料,构建库容量为2.1×106pfu/mL的cDNA文库。通过对文库中克隆子的序列测定和生物信息学初步分析,得到1323条有效EST序列。经BlastX及BlastN软件进行同源对比分析,653条(49.36%)EST可在蛋白质或核苷酸水平上找到同源序列,其中328条与七鳃鳗科物种同源。同源序列功能分类大致分为11类,与蛋白质合成有关的蛋白所占比例最大。1323条EST进行片段重叠群分析(contig analysis)获得包括547条序列在内的162组片段重叠群并确定了8条全长cDNA。日本七鳃鳗口腔腺cDNA文库以及EST文库的成功构建,为研究日本七鳃鳗口腔腺的功能基因和蛋白质组学奠定了基础。

Expressed Sequence Tags (ESTs) Analysis of the Oral Gland of Lampetra japonica

A cDNA library (2. 1 ×106 pfu/mL) was constructed from the oral gland of Lampetra japonica. After random selection of clones for sequencing, 1 323 clones with inserts longer than 100 bp and with good chromato-grams were obtained. Using BlastX and BlastN programs,We found 653 ESTs(49.36% ) that shared significant homology with known sequences in protein or nucleotide databases of NCBI,including 328 ESTs homologous to known sequences of Petromazonidae animals. These ESTs were classified into 11 different functional categories,the highest proportion of which was related to protein synthesis. Out of the 1 323 ESTs,162 non-redundant contigs were assembled from 547 sequences after alignment using software at the threshold of more than 90% homology over a minimum of 20 base pairs. There were eight full-length cDNAs with complete open reading frame. Further studies on the ESTs in the library may be helpful to elucidate the components of Lampetra japonica oral gland and to understand the function of those proteins at the molecular level.