BMC Genomic文章：果蝇幼虫睾丸mRNA表达差异的研究

　　Wolbachia是在无脊椎动物体内普遍存在的共内生细菌。它们在宿主的细胞内通过雄性抹杀，雌性化，孤雌生殖，细胞质不相容（Cytoplasmic Incompatibility，CI）等方式影响着宿主的生殖。CI是在昆虫中最常见的表现型。当Wolbachia感染的雄性与未感染的或者感染不同Wolbachia的雌性进行交配繁殖，胚胎的发育会被终止。虽然CI的分子机理目前还不清楚，但是有些报道显示Wolbachia会在宿主的精子形成过程中影响精子。

华中师范大学生命科学学院的王玉凤教授利用果蝇的表达谱芯片15K Droso-phila Genome Array比较了80对果蝇幼虫睾丸的mRNA表达差异。在荧光定量PCR验证后，发现12个基因的表达存在明显差异。通过原位杂交实验，证明了Wolbachia感染会改变与精子形成相关的基因表达，包括保幼激素、免疫和新陈代谢。

上述研究中，果蝇表达谱芯片服务在博奥生物有限公司完成。

原文摘要：

Differentially expressed profiles in the larval testes of Wolbachia infected and uninfected Drosophila

Background:Wolbachiaare endosymbiotic bacteria that are frequently found in arthropods and nematodes. These maternally inherited bacteria manipulate host reproduction by several mechanisms including cytoplasmic incompatibility (CI). CI is the most common phenotype induced by Wolbachiaand results in the developmental arrest of embryos derived from crosses between Wolbachia-infected males and uninfected females. Although the molecular mechanisms of CI are currently unknown, several studies suggest that host sperm is modified by Wolbachiaduring spermatogenesis.

Results:We compared the gene expression of Drosophila melanogasterlarval testes with and without thewMel strain of Wolbachiato identify candidate genes that could be involved in the interaction betweenWolbachiaand the insect host. Microarray, quantitative RT-PCR and in situ hybridization analyses were carried out on D.melanogaster larval testes to determine the effect of Wolbachiainfection on host gene expression. A total of 296 genes were identified by microarray analysis to have at least a 1.5 fold change [q-value < 5%] in expression. When comparingWolbachia-infected flies to uninfected flies, 167 genes were up-regulated and 129 genes downregulated. Differential expression of genes related to metabolism, immunity, reproduction and other functions were observed. Quantitative RT-PCR (qRT-PCR) confirmed 12 genes are differentially expressed in the testes of the 3rd instar larvae ofWolbachia-infected and uninfected flies. In situhybridization demonstrated that Wolbachia infection changes the expression of several genes putatively associated with spermatogenesis including JH induced protein-26 and Mst84Db, or involved in immune (kenny) or metabolism (CG4988-RA).

Conclusions:Wolbachiachange the gene expression of 296 genes in the larval testes of D. melanogaster including genes related to metabolism, immunity and reproduction. Interestingly, most of the genes putatively involved in immunity were up-regulated in the presence of Wolbachia. In contrast, most of the genes putatively associated with reproduction (especially spermatogenesis) were down-regulated in the presence of Wolbachia. These results suggest Wolbachiamay activate the immune pathway but inhibit spermatogenesis. Our data provide a significant panel of candidate genes that may be involved in the interaction between Wolbachiaand their insect hosts. This forms a basis to help elucidate the underlying mechanisms of Wolbachia-induced CI in Drosophilaand the influence of Wolbachiaon spermatogenesis.

原文出处：http://www.biomedcentral.com/1471-2164/12/595