Gene expression profiles in mouse pachytene spermatocytes and round spermatids revealed by cDNA microarray

Spermatogenesis is a highly complex process and many genes are involved in its regulation, but relatively few genes have been identified. To gain a comprehensive view of gene expression and of the regulatory mechanism involved in germ cell development, we used a mouse 8.0K cDNA chip to compare the gene expression profiles of mouse pachytene spermatocytes and round spermatids, which were isolated from 9-week ICR mice testes by velocity sedimentation under unit gravity (VSUG). We verified differentially expressed genes by semi-quantitative and real-Time RT-PCR, and found that the expression of 32 genes was higher in pachytene spermatocytes than in round spermatids, and 25 in round spermatids than in pachytene spermatocytes. In pachytene spermatocytes, the expression of cell cycle and proliferation-related genes, CDC2a, CDK2, CDC7, CKS2 and PCNA was increased over two-fold. In round spermatids, the expression levels of ubiquitin-related genes, USP16, USP9X and Ube2n were up regulated. The expression of the RNA binding motif (RBM) protein, RBMX, was increased over two-fold in pachytene spermatocytes, and RBM4 was increased in round spermatids. The genes identified include; primarily chromosomal genes related to intracellular enzyme and nucleic acid binding proteins, and kinase and substrate genes that mediate cell cycle transition. This dynamic gene expression and localization during spermatogenesis may be critical for the meiotic cell division process and germ cell development.