中文摘要：

周期蛋白A（cyclinA）能分别与2种重要的周期蛋白依赖性激酶cdk1和cdk2作用,推动细胞周期的正常进行。利用家蚕基因组数据和分子生物学方法克隆了cyclinA基因在家蚕中的同源物BmcyclinA（GenBank登录号：FJ619105）,发现了BmcyclinA基因的另一种错误剪接形式BmcyclinA-1。BmcyclinA基因位于家蚕第13号染色体,由7个外显子和6个内含子组成,其完整开放阅读框为1 533 bp,编码511个氨基酸,在248^th-450^th氨基酸区域存在2个保守的周期蛋白框。BmcyclinA-1仅能编码正常cyclinA蛋白N端的153个氨基酸残基。RT-PCR分析显示BmcyclinA基因在家蚕整个胚胎发育时期及5龄第3天各组织中均有表达,并且在幼虫精巢中的表达相对较高。

英文摘要：

CyclinA plays an important role in cell cycle by binding cdk1（cyclin-dependent kinase 1） or cdk2 to form kinase complexes.In present study,a cyclinA homologous gene in Bombyx mori,designated BmcyclinA,was cloned from silkworm genome data and through molecular biological method（GenBank accession No.FJ619105）.Sequence analysis revealed a failure splicing product named BmcyclinA-1.BmcyclinA gene is located on the 13^th chromosome with 7 exons and 6 introns.It contains an open reading frame of 1 533 bp in length and encodes for 511 amino acids.There are two conservative cyclin boxes in the 248^th to 450^th amino acids.However,BmcyclinA-1 only codes for the 153 amino acids of the normal cyclinA.RT-PCR results indicated extensive expression of BmcyclinA during embryogenesis and in tissues of day 3 larvae of the 5th instar with relatively higher expression level in larval testis.