【摘要】 前期研究发现在感染家蚕质型多角体病毒（Bombyx mori cytoplasmic polyhedrovirus,Bm CPV）的家蚕幼虫中肠中,有一个下调表达的差异蛋白可能参与了家蚕对Bm CPV感染的抵抗过程。利用Blastp进行同源性比对的结果显示,该蛋白质与尺蠖（Operophtera brumata）的未知蛋白质OBRU01₀4785和蜕皮激素22激酶（Ecdysteroid 22-kinase）的序列相似度分别为51%、49%,进一步通过多序列比对和系统进化分析发现该蛋白质与Ecdysteroid 22-kinase蛋白的亲缘关系最近,属于蜕皮激素激酶超家族;该蛋白质与家蚕中已知的蜕皮激素22激酶1（Bm Ec K1）的序列相似度为24.4%,因此将其命名为Bm Ec K2。实时荧光定量PCR检测Bm Ec K2基因m RNA在家蚕5龄幼虫中肠组织中的转录水平最高,其次是马氏管、丝腺和卵巢,而在血淋巴、头部、精巢、脂肪体中几乎检测不到转录;家蚕5龄起蚕感染Bm CPV后24、48、72 h,中肠中Bm Ec K2基因m RNA的转录水平下调,分别是对照组家蚕中肠的0.32、0.45和0.21倍。研究结果初步提示,Bm CPV感染导致家蚕中肠中的Bm Ec K2下调表达,进而可能影响到家蚕体内激素调节水平的变化。更多还原

【Abstract】 Our previous study identified a down-regulated protein in larval midgut of silkworm infected by Bombyx mori cytoplasmic polyhedrovirus（ Bm CPV）. This differentially expressed protein might be involved in resistance of silkworm against Bm CPV infection.Blastp search revealed that this protein has 51 % and 49 % sequence identity with hypothetical protein OBRU01₀4785 and Ecdysteroid22-kinase of Operophtera brumata. Sequence alignment and phylogenic analysis indicated that this protein has the closest evolutionary relationship with ecdysteroid 22-kinase,belonging to the ecdysteroid kinase superfamily. Since this protein has 24. 4 % sequence identity with Bombyx mori ecdysteroid 22-kinase 1（ Bm Ec K1）,it was thus named Bm Ec K2. Real-time fluorescent quantitative PCR（ q RTPCR） analysis displayed that the m RNA transcriptional level of Bm Ec K2 gene was the highest in larval midgut,followed by Malpighiantubule,silk gland and ovary. m RNA of Bm Ec K2 gene was hardly detectable in larval hemocytes, head, testicle and fat body of the 5 th instar silkworm larvae. m RNA transcriptional level of Bm Ec K2 gene in midgut of the 5 th instar newly exuviated larvae infected by Bm CPV was down-regulated, being 0. 32-,0. 45- and 0. 21-fold to that of the control at 24 h,48 h and 72 h post-inoculation,respectively. The above result suggested thatBm CPV infection could induce down-regulation of Bm Ec K2 gene,which may further influence hormonal regulation in the silkworm.更多还原