DNA methylation and alternative splicing modulate FBXW11 gene expression in Holstein bull testis and are correlated with sperm quality

F-box and WD-40 domain protein 11(FBXW11)is an important component of the E3 ubiquitin-ligase enzyme that plays a key role in the ubiquitin-dependent regulation of spermatogenesis.In our previous research,the mRNA expression of FBXW11 in bull sperm with high motility is significantly higher than that with low motility.In the present study,the protein expression levels of FBXW11 in bull testicular tissues with low-performance sperm quality groups were significantly higher than those in normal performance groups.The immunohistochemistry result demonstrated that FBXW11 protein was located in the periphery of Leydig cells and seminiferous tubules.Three splice variants of the FBXW11 gene,namely,FBXW11-tv1,FBXW11-tv2,and FBXW11-tv3,were identified in testicular tissues.The splicing patterns of the three variants are exon skipping.The transcript FBXW11-tv2 expressions were the highest in each sample.The low-performance groups displayed higher FBXW11-tv1 and FBXW11-tv2 transcript expressions than the normal performance groups.Two CpG islands were located within the 5’UTR and exon 1-2 region of the FBXW11 gene.Bisulfite sequencing PCR results demonstrated that the methylation levels of 11 methylation sites in the CpG island 2 from−99 to−43 in the normal performance groups were significantly lower than those in the low-performance groups.Pearson correlation analysis suggested that the CpG island 2 methylation level was negatively correlated with sperm motility and the transcript FBXW11-tv2 expression level.Our data revealed that alternative splicing and DNA methylation jointly regulated FBXW11 gene expression and were correlated with sperm quality traits during spermatogenesis in Holsteins.

Expression pattern and regulation of head-to-head genes Vps36 and Ckap2 during chicken follicle development

Vacuolar protein sorting 36(VPS36),a protein primarily known for its role in the Endosomal Sorting Complex Required for Transport pathway,has recently been shown to be linked to chicken reproduction.Previous research showed that Vps36 is significantly downregulated in sexually mature chicken ovaries compared to immature ones.In this study,using real-time quantitative RT-PCR,we investigated the expression pattern of Vps36 and its head-to-head gene Ckap2 mRNA in chicken follicles.Small white follicles were found to have significantly higher expression of Vps36 and Ckap2 mRNA than any other sized follicles(P<0.05).The expression of Vps36 and Ckap2 mRNA were detected in both granulosa and theca layers of pre-ovulatory follicles,the expression of Ckap2 in theca layers was slightly higher than in granulosa cells.Treatment of small yellow follicles with folliclestimulating hormone and estradiol resulted in a marked decrease of both Vps36 and Ckap2 mRNA(P<0.05);however,progesterone,transforming growth factor-β1 and luteinizing hormone induced no significant changes in Vps36 and Ckap2 mRNA expression in these follicles.These results indicate that the head-to-head genes of Vps36 and Ckap2 exhibit similar expression in chicken follicles and are involved in chicken follicle development.