家蚕微孢子虫反转录酶基因部分序列的克隆与分析

从家蚕微孢子虫 (Nosemabombycis)中通过RT PCR扩增出反转录酶 (reversetranscriptase)基因的部分序列(大小为 1 2kb) ,经 3′ RACE(RapidAmplificationofcDNAEnds)获得其 3′端序列 ,但经两次 5′ RACE后仍未发现起始密码子 (ATG)。目前得到的cDNA序列为 330 3bp ,推测其编码 110 1个氨基酸的多肽 ,经同源性比较分析 ,发现该序列与许多生物体的反转录酶基因有一定的同源性。

Cloning and Characterization of a Gene Coding ReverseTranscriptase From Nosema bombycis

Partial cDNA sequence about 1.2kb coding reverse transcriptase gene from Nosema bombycis was amplified by RT PCR.After cloning and sequencing,the result showed that there were not original codon and stop codon.So gene specific primers were designed based on the sequence to amplify its 5′ terminal and 3′ terminal sequences.After that,the products of 3′ RACE showed that there were stop codon (TGA) and polyA in the 3′ end.But the original codon (ATG) hasnt been found after 5′ RACE for twice.Ultimately,we got cDNA sequence for 3 303bp and predicted a peptide of 1 101 amino acids,but not full length.And then we used BLAST to consult GenBank database and knew it was high homologous with reverse transcriptase genes of many organisms.