Abstract: 【Objective】 The aim of this experiment was to explore the mechanism of Y chromosome (Zfy) gene during the development of sperm tails in adult male mice.【Method】 Twenty 8-week-old Kunming strain (KM) male mice were selected and divided into experimental and control groups,with 10 mice in each group.The mouse testis Zfy gene interference model was established by injecting the Zfy gene interference vector and the mixture of Lipofectamine^TM LTX & PLUS^TM transfection reagent into the rete testis,and injecting the empty vector and the mixture of Lipofectamine^TM LTX & PLUS^TM transfection reagent into the rete testis as the control group.After injection for 72 hours,testis tissues from both groups were collected for detecting the interference effect of Zfy gene interference vector on testis Zfy gene by Real-time quantitative PCR,and measuring the expression changes of SUN5,CATSPER1 and Odf1 genes related to the development of sperm tail of mice.The protein expression levels of the above genes were detected by Western blotting.The correlation between Zfy protein and SUN5,CATSPER1 and Odf1 proteins were detected by immunoprecipitation.The epididymal sperm of experimental and control groups were collected,for comparing the changes of 8 head and tail malformation rates by eosin sperm staining,and detecting the changes of sperm movement parameters by computer assisted sperm analysis (CASA) system.【Result】 After interference for 72 hours,compared with the control group,the mRNA and protein relative expression levels of Zfy gene in experimental group were extremely significant decreased (P＜0.01).The mRNA and protein relative expression levels of SUN5,CATSPER1 and Odf1 genes in testis of experimental group were extremely significantly decreased (P＜0.01).Zfy protein could form immunoprecipitation complex with SUN5 and CATSPER1 proteins.Compared with control group,the rates of head without hook deformity,abnormally large head deformity,amorphous deformity,tail folding deformity,tail curling deformity and tail breaking deformity of mouse sperm in the experimental group were extremely significant or significantly increased (P＜0.01 or P＜0.05).The results of CASA showed that compared with the control group,the semen parameters (sperm density,motility,progressive motility) and sperm locomotion parameters (curvilinear velocity,straight-line velocity,average path velocity,amplitude of lateral head displacement,linearity,wobble,straightness and beat-cross frequency) of mouse in experimental group were significantly or extremely significantly decreased (P＜0.05 or P＜0.01). 【Conclusion】 The expression levels of SUN5,CATSPER1 and Odf1 genes and their proteins decreased in the Zfy gene interference model of mouse testis,which affected the head-tail connection of sperm,the energy supply of tail motor and the formation of outer layer structure of tail flagella,resulting in the abnormality of sperm tail and the decrease of motor ability.

Key words: Zfy gene; sperm tail development; gene interference