Sex control by Zfy siRNA in the dairy cattle.

Zinc-finger Y is located in the short arm of the Y-chromosome and is a highly conserved gene that plays an important role in spermatogenesis. The objective of this study was to investigate the influence of silencing the Zfy gene during spermatogenesis on Y-sperm formation and offspring sex determination in Bos taurus cattle. Three recombinant expression vectors pLL3.7/a, pLL3.7/b and pLL3.7/c were evaluated and only pLL3.7/a effectively silenced the Zfy gene. The pLL3.7/a recombinant expression vector was injected into bull testes, using three injections. Semen was collected and preserved by extending and freezing. The frozen semen was subsequently used in artificial insemination of cows during a breeding season in accordance with the production plan on the farm where the experiment was conducted. Results showed that, after exposure to pLL3.7/a, sperm motility decreased (P < 0.01), but the sperm density was similar (p > 0.05) to the non-treated control semen. Injection of pLL3.7/a resulted in 72.0% female offspring, and was greater than the 49.4% female calves in the control (P ＜ 0.01), Results from this research suggests that the Zfy gene plays a role in the process of Y-sperm formation, and Zfy siRNA is a potential useful approach to control sex of offspring in cattle.

RNAi as a tool to control the sex ratio of mouse offspring by interrupting Zfx/Zfy genes in the testis.

The objective of this study was to explore a novel method to alter the sex-ratio balance of mouse offspring by silencing the paralogous genes Zfx/Zfy (Zinc finger X/Y-chromosomal transcription factor gene) during spermatogenesis. Four recombined vectors PRZ1, PRZ2, PRZ3, and PRZ4 (RNAi-Ready-pSIREN-RetroQ-ZsGreen) were constructed for interrupting the Zfx gene. Additionally, a recombined vector Psilencer/Zfy-shRNA was constructed for interrupting the Zfy gene. Male mice were randomly divided into 8 groups, with 20 animals per group. Five groups of mice were injected with PRZ1, PRZ2, PRZ3, PRZ4, and Psilencer/Zfy-shRNA vectors, respectively. The three control groups were injected with an equal volume of physiological saline, empty RNAi-Ready-pSIREN-RetroQ-ZsGreen vector, and empty Psilencer/Zfy-shRNA vector, respectively. All groups were injected every 7 days for a total of four injections. Fourteen days after the fourth injection, 10 male mice from each group were mated individually with 10 females. Testicular tissue of 10 male mice in each group was collected, and the expression level of Zfx/Zfy mRNA was determined by qRT-PCR. Results showed that, compared with the empty RNAi-Ready-pSIREN-RetroQ-ZsGreen vector and the physiological saline group, expression of Zfx mRNA decreased significantly after injection of PRZ1 (p < 0.01), PRZ3 (p < 0.01), and PRZ4 (p < 0.01), and 78.75 ± 7.50% of the offspring were male in PRZ4 group, significantly higher than the offspring derived from the empty RNAi-Ready-pSIREN-RetroQ-ZsGreen vector and physiological saline group (p < 0.01). In the PRZ1 group, the expression of Zfx mRNA was also significantly lower (p < 0.01), but the male rate of offspring was not different (p > 0.05). Conversely, the expression of Zfy mRNA decreased significantly after injection of Psilencer/Zfy-shRNA (p < 0.01) and 31.00 ± 11.00% of the offspring were male, significantly lower than in the physiological saline group (p < 0.01). In conclusion, our findings show that RNAi-mediated disruption of Zfx/Zfy in mouse testis affected X/Y spermatogenesis. Additionally, results suggest that the paralogous genes Zfx/Zfy play an important role in the process of X and Y sperm development. The individual interference of Zfx/Zfy may predict the outcome of X and Y haploid sperms. Presented herein is an advanced method developed to control mouse X/Y spermatogenesis and sex ratio of offspring.