家蚕Osiris基因家族成员的系统进化与组织表达芯片分析

Phylogenetic and Tissue Expression Microarray Analyses on Family Members of Bombyx mori Osiris Genes

昆虫特有基因对于维持昆虫特有的形态、行为及生活习性起关键作用,同时也是防治有害昆虫的靶标基因。基于家蚕基因组数据,对昆虫特有基因Osiris(Osi)家族进行了分析。通过同源比对,发现家蚕的Osi家族含有22个成员,其中21个基因串联分布在26号染色体,1个基因位于4号染色体。共线性分析发现,家蚕与黑腹果蝇有18个Osi基因表现为共线性关系。系统进化分析表明Osi基因家族是在昆虫物种分化前已形成的多基因家族,家蚕与果蝇的Osi家族亲缘关系相对较近。家蚕的4个Osi基因(BmOsi9-1、BmOsi9-3、BmOsi9-4和BmOsi9-5)聚成一个进化枝,且在基因组上呈串联分布,暗示其是在物种分化后通过基因复制产生的,属特有基因。结构域分析发现,家蚕Osi蛋白均含有一个功能未知的结构域DUF1676,是Osi基因家族的典型特征。组织芯片分析表明,BmOsi20和BmOsi17分别在家蚕5龄幼虫的中肠和精巢中特异性高量表达,BmO-si18和BmOsi9-1分别在马氏管和丝腺中特异表达。

Insect-specific genes play a key role in maintaining their characteristic morphology, behaviors and life habits. Meanwhile, they are also target genes for controlling harmful insects. Based on the silkworm （ Bombyx mori） genome database, the present study analyzed an insect-specific gene Osiris （Osi） family. Homologous alignment showed that silkworm had 22 members in Osi gene family, among which 21 were located on chromosome 26 and 1 was located on chromosome 4. Synteny analysis showed that 18 Osi genes displayed syntenic relationship between B. mori and Drosophila melanogaster. Phylogenetic analysis indicated that Osi gene family had been formed before insect speciation. The evolu-tionary relationship was relatively close between B. mori and D. melanogaster. 4 silkworm Osi genes （ BmOsi9-1, BmOsi9-3, BmOsi9-4 and BmOsi9-5 ） formed a mono- phyletic clade in phylogenetic tree and were distributed in a tandem pattern on the chromosome, implying that they were expanded by gene duplication events after species 3peciation and were thus species-specific genes. Struc- Lural domain analysis revealed that all silkworm Qsi proteins contained a structural domain （DUF1676） of unknown function, being a typical feature of Osi gene family. Expression profile based on the microarray analyses to the 5th instar silkworm larvae showed that BmOsi2O and BmOsi17 were specifically and highly expressed in midgut and testis respectively, and BmOsi18 and BmOsl9-1 were specifically expressed in Malpighian tubule and silk gland respectively.