中文摘要：

在感染家蚕质型多角体病毒（BmCPV）的家蚕中肠组织中发现一个差异表达的假定蛋白基因。利用cDNA末端快速扩增（RACE）技术克隆了该假定蛋白基因的全长cDNA。用生物信息学方法进行基因序列与结构分析表明：该基因全长cDNA序列为486bp,包含108bp的5′端非翻译区序列（5′-UTR）和153bp的3′端非翻译区序列（3′-UTR）,开放阅读框（ORF）为225bp,编码74个氨基酸,蛋白分子质量为6.888kD,等电点为5.27;该基因由3个外显子和2个内含子组成,ORF位于第2外显子内,编码蛋白含二次跨膜结构,多肽链表现为疏水性,在多肽链上的第15～16氨基酸残基可能是信号肽的切割位点。RT-PCR结果显示该基因在家蚕5龄幼虫的丝腺、血液、脂肪体、生殖腺及中肠组织中均有表达;荧光定量PCR结果表明该基因在感染Bm-CPV的家蚕中肠组织中的表达水平为正常家蚕中肠组织的6.28倍。研究结果为进一步解析该基因的功能奠定了基础。

英文摘要：

A differentially expressed hypothetic protein gene was identified in the midgut of silkworm （Bombyx mori） larvae infected with Bombyx mori cytoplasmic polyhedrosis virus.Full-length cDNA of the hypothetic protein was cloned by using rapid amplification of cDNA ends （RACE）.Analysis of the gene sequence and structure by means of bioinformatics revealed that the full-length cDNA was 486 bp long,consisting of a 108 bp 5＇-untranslated region,a 153 bp 3＇-untranslated region and a 225 bp open reading frame （ORF） which encodes a 74 amino acid protein.Molecular weight of the hypothetic protein is 6.888 kD and the isoelectric point is 5.27.The cDNA sequence of this gene consists of 3 exons and 2 introns and the ORF is located within the second exon.The protein contains 2 trans-membrane domains and the overall polypeptide chain is hydrophobic.Cleavage site of the signal peptide is predicted to be between the 15th and 16th amino acid resides.RT-PCR analysis suggested that the hypothetic protein gene was expressed in all the tissues tested,including silk gland,hemocyte,fat body,gonad and midgut.Fluorescent quantitative polymerase chain reaction analysis indicated that the relative transcript of the hypothetic protein gene in the infected midgut was 6.28 folds that in the normal midgut.Our results provide useful information for further studies on function of this hypothetic protein in silkworm.