RESUMO
Objective Whether the Ubi-p63E gene regulates spermatogenesis and tumorigenesis remains unclear. This study aimed to explore the regulatory effect of Ubi-p63E on germline stem cells (GSC) in the GSC niche of the Drosophila testis. Methods We used the UAS-Gal4 system for knockdown of the Ubi-p63E gene in the specific GSCs of the Drosophila testis and divided the male flies for this experiment into three groups: control (wild-type W1118 flies), nos>Ubi-p63E RNAi (knockdown of the Ubi-p63E gene in the early germ cells), and tj>Ubi-p63E RNAi (knockdown of the Ubi-p63E gene in the cystoblasts). We determined the fertility rate of the flies by fertility tests and examined the effect of Ubi-p63E on the Drosophila testis in the GSC niche by immunofluorescence staining. Results Fertility tests manifested a significantly lower rate of fertility in the nos>Ubi-p63E RNAi and tj>Ubi-p63E RNAi groups than in the control (0.00% and 4.12% vs 97.26%, P < 0.01). Morphologically abnormal testes were observed in the nos>Ubi-p63E RNAi and tj>Ubi-p63E RNAi groups, only 22.77% and 18.86% as long as the testes of the control flies. Immunofluorescence staining revealed no morphologically normal testes in the tj>Ubi-p63E RNAi group, but quite a few masses of abnormal cells, and mostly Vasa-positive cells. Conclusion The Ubi-p63E gene affects the self-renewal ability of GSCs in the GSC niche of the Drosophila testis as well as the differentiation of GSCs via cystoblasts, and consequently leads to the formation of germ cell tumors.