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Polycomb group(PcG)蛋白是多细胞有机体中的一类表观遗传抑制因子,Ring是PcG蛋白家族的主要成员,在PcG蛋白的转录抑制调控中行使重要功能,对昆虫和哺乳动物的发育至关重要.利用同源检索方法获得家蚕Ring基因(BmRing)的核苷酸序列,该基因位于家蚕第17号染色体的nscaf2865位点.BmRing的核苷酸序列由4个外显子和3个内含子构成,基因的cDNA3'端有2个多聚腺苷酸化信号(aat aaa)和典型的poly(A)结构;BmRing编码由377个氨基酸组成的蛋白质,分子质量为41.8 kD,等电点为6.72,氨基酸序列具有3个同源异型结构域(homeobox domain,HD),46～85 aa为高度保守的典型的环指结构域(Ringfinger),331～347 aa为跨膜区,N端位于膜外.通过STRING在线预测分析得到10个与BmRing有相互作用关系的蛋白质.系统进化分析显示BmRing与果蝇的DmSCE、意大利蜜蜂的AmRing等的亲缘关系较近.以家蚕5龄第3天幼虫的卵巢cDNA为模板,克隆了BmRing基因,并利用半定量RT-PCR检测BmRing基因在5龄第3天幼虫的精巢、卵巢、头部和血细胞中有明显表达,而在其他组织中几乎不表达.获得的上述基础信息,有益于进一步研究BmRing的生物学功能.“,”Polycomb group (PcG) proteins are important epigenetic repressors in metazoans.Ring is an important member of PcG protein family,which plays an essential regulatory role in development of insects and mammals.We obtained a homolog of Ring gene from silkworm (Bombyx mori) successfully through in silico cloning,and designated this gene as BmRing.This gene is located on nscaf2865 of silkworm chromosome 17 and consists of 4 exons and 3 introns.3'terminal of its mRNA sequence contains two polyadenylation signal (aataaa) and a typical poly(A) structure.The encoded protein is composed of 377 amino acids with a molecular weight of 41.8 kD and an isoelectric point of 6.72.The protein has three homeobox domains (HDs),one highly conserved typical Ring finger domain at 46-85 amino acids,one transmembrane domain at 331-347 amino acids with its N-terminal outside the membrane.Ten interacting proteins with BmRing were obtained by STRING online analysis.Phylogenetic analysis showed that BmRing has close relationships with DmSCE from the fruit fly (Drosophila melanogaster) and AmRing from the honey bee (Apis mellifera).BmRing gene was cloned using ovary cDNA of day 3 silkworm larvae of the 5th instar as template.Semiquantitative RT-PCR analysis displayed that BmRing gene was obviously expressed in testis,ovary,head and hemocytes of day 3 larvae of the 5th instar,while almost no expression was observed in other tissues.The obtained data are favorable for further exploration of biological functions of BmRing gene.