Objective: To investigate the expression pattern of the D930020B18Rik gene in the testis of the mouse in different stages of development and its possible role in spermatogenesis.
Methods: Using gene expression profile microarray, we identified highly expressed D930020B18Rik in the mouse testis and analyzed the expression pattern of the gene by qPCR, immunohistochemistry, Western blot and immunofluorescence staining, and verified its function and molecular mechanism using bioinformatics analysis, dual-luciferase reporter assay and cell cycle synchronization.
Results: The expression of the D930020B18Rik gene remained low in the testis of the mouse and mainly localized in the cytoplasm of spermatogonia during the first 2 postnatal weeks (PNW), increased from the 3rd PNW to sexual maturity, localized in the cytoplasm of spermatogonia and the nuclei of round and elongated spermatids, but was absent in the nuclei of mature sperm. Phylogenetic analysis showed that the D930020B18Rik protein sequence was highly conserved in mammals. Gene set enrichment analysis indicated that D930020B18Rik and its homologous protein might be involved in regulating spermatogenesis of mammals by participating in nucleoplasmic condensation (normalized enrichment score ［NES］ = 1.652, P < 0.01, false discovery rate ［FDR］ = 0.153), meiosis (NES = 1.960, P < 0.01, FDR = 0.001) and formation of microtubule cytoskeleton during mitosis (NES = 1.903, P < 0.01, FDR = 0.009). Dual-luciferase reporter assay revealed that the transcription factors klf5 and foxo1 could identify and bind D930020B18Rik promoters and perform the function of positive or negative transcriptional regulation.
Conclusion: The D930020B18Rik gene is expressed in the mouse testis in a time- and location-specific manner, highly associated with spermiogenesis, mainly localized in the nuclei of germ cells, and may be involved in the meiosis of spermatocytes and spermiogenesis.
Keywords: D930020B18Rik; spermatogenesis; testis; mouse.