BMC Genomic文章：果蠅幼蟲睪丸mRNA表達差異的研究
Wolbachia是在無脊椎動物體內普遍存在的共內生細菌。它們在宿主的細胞內通過雄性抹殺，雌性化，孤雌生殖，細胞質不相容（Cytoplasmic Incompatibility，CI）等方式影響著宿主的生殖。CI是在昆蟲中最常見的表現型。當Wolbachia感染的雄性與未感染的或者感染不同Wolbachia的雌性進行交配繁殖，胚胎的發育會被終止。雖然CI的分子機理目前還不清楚，但是有些報道顯示Wolbachia會在宿主的精子形成過程中影響精子。
華中師范大學生命科學學院的王玉鳳教授利用果蠅的表達譜芯片15K Droso-phila Genome Array比較了80對果蠅幼蟲睪丸的mRNA表達差異。在熒光定量PCR驗證后，發現12個基因的表達存在明顯差異。通過原位雜交實驗，證明了Wolbachia感染會改變與精子形成相關的基因表達，包括保幼激素、免疫和新陳代謝。
上述研究中，果蠅表達譜芯片服務在博奧生物有限公司完成。
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.
原文出處：http://www.biomedcentral.com/1471-2164/12/595