丝氨酸/精氨酸蛋白特异激酶SRPK2在小鼠睾丸组织中的表达及意义

Expression and significance of SR-protein-specific kinase SRPK2 in mouse testis

目的通过研究丝氨酸/精氨酸蛋白特异激酶2(serine/arginine-rich protein specific kinase 2,SRPK2)基因mRNA及其编码蛋白产物在小鼠睾丸组织中的表达特征,探讨该基因在精子发生过程中的作用及意义。方法分别采用半定量逆转录聚合酶链反应(RT-PCR)和蛋白免疫印迹杂交(Western blotting)分析该基因mRNA及蛋白产物在小鼠多种组织中的表达;利用实时定量PCR(real-time quantitative PCR)分析SRPK2 mRNA在不同发育阶段小鼠睾丸组织中的差异表达;应用免疫组织化学染色和间接免疫荧光技术观察SRPK2蛋白在小鼠曲精小管中的细胞定位和生精细胞内的亚细胞定位。结果半定量RT-PCR和Western blotting分析显示SRPK2 mRNA和蛋白在小鼠睾丸组织中均大量表达;实时定量PCR分析发现SRPK2 mRNA在5周及8周龄雄性小鼠睾丸组织中显著表达,具有明显的阶段特异性表达特征。免疫组织化学染色结果表明SRPK2蛋白阳性着色主要位于曲精小管中的长形精子细胞核;间接免疫荧光分析显示SRPK2蛋白定位于长形精子细胞核表面。结论 SRPK2基因在小鼠睾丸组织中大量表达,并且具有显著的阶段特异性表达特征和明确的细胞核定位,极有可能在小鼠精子发生的变态成形期参与mRNA前体分子的剪接过程,其作用机制值得进一步深入研究。

Objective To analyze the expression characteristics of SRPK2 （ serine /arginine-rich protein specific kinase 2 mRNA and its encoded protein products in mouse testis, and to reveal its molecular role during spermatogenesis. Methods Using semi-quantitative reverse transcription polymerase chain reaction （ RT-PCR） and Western blotting to an-alyze the expression of SRPK2 mRNA and its protein products in several mouse tissues.The stage-specific expression pat-tern of SRPK2 mRNA in mouse testis was examined by real-time quantitative PCR.Immunohistochemical staining was ap-plied to identify the SRPK2 protein distribution in mouse testicular seminiferous tubules and indirect immunofluorescence staining was used to detect the subcellular localization of SRPK2 protein in spermatic cells.Results Semi-quantitative RT-PCR and Western blotting analysis revealed that SRPK2 was highly expressed in mice testis.Real-time quantitative PCR analysis showed that SRPK2 mRNA was expressed abundantly at the stage of 5-and 8-week old mouse testes, suggesting that SRPK2 gene has stage-specific expression patterns during mouse spermatogenesis.Immunohistochemical and indirect immu-nofluorescence staining demonstrated that SRPK2 protein was located around the surface of elongated sperm nucleus. Conclusions SRPK2 is highly expressed in mouse testis and has significant stage-specific expression characteristics with distinct nuclear localization.These results indicate that SRPK2 may participate in precursor mRNA splicing during mouse spermiogenesis.The molecular mechanism of SRPK2 is yet to be further studied.