LncRNA4667 is dispensable for spermatogenesis and fertility in mice

Objective: Spermatogenesis is a complex process which is of vital importance for sexual reproduction. In many studies of spermatogenesis, the mRNAs, protein-coding genes, as well as small noncoding RNAs (ncRNAs) have been well characterized. However, there remain numerous questions despite previously characterized molecular mechanisms. Long ncRNAs (lncRNAs) are a relatively new addition to our knowledge of ncRNAs. Limited studies have examined the function of lncRNAs in spermatogenesis. Therefore, we selected a testis-specific lncRNA, lncRNA4667, to analyze its potential role in spermatogenesis and male fertility. Methods: In situ hybridization and quantitative reverse transcription polymerase chain reaction analyses were used to confirm testis-specific expression of lncRNA4667. LncRNA4667 knockout mice were generated using CRISPR/Cas9 technology. Histology, sperm counts, sperm motility, body parameters, and fertility were compared between wild-type and knockout mice (n = 8/group). Results: Expression analysis showed that lncRNA4667 was testis specific and localized to round spermatids in seminiferous tubules of adult mouse testes. Mice homozygous for a null mutation of lncRNA4667 displayed normal spermatogenesis and fertility compared with wild-type mice. Conclusions: These data indicate that lncRNA4667 is dispensable for spermatogenesis and fertility in mice, and the localization of lncRNA4667 makes it a useful marker for the identification of round spermatids in mice