Transcriptional Regulation Mechanism Of Anovel Human Gene SPATA12

SPATA12is a novel human spermatogenesis associated gene. In previous study, it has been shown that SPATA12is a stage-specific gene which plays some roles in the differentiation phase of spermatogenesis, including inhibiting cell inhibition and/or maintenance of the cell in a differentiated state. But nothing is known regarding the transcriptional activation or regulation of SPATA12.In this paper, bioinformatics analysis was first used to predict the region of SPATA12and to reveal multiple potential binding sites of transcription factors including SMAD, AP-1, HSF and GCR-1and so on. By generating a series of progressive deletion SPATA12gene promoter constructs, we next identified the core promoter which is located within the77-302regions, in which include one potential AP-1binding site, one SRY binding site and one HSF binding site. The promoter activity of point mutation construct or deletion construct of AP-1binding site was decreased obviously compared to the wild type construct, suggesting that AP-1binding site is important for the basal transcriptional activity of SPATA12promoter and SPATA12gene is regulated by AP-1transcription factor at least at the transcriptional level. Further, results showed that TGF-β1treatment could induce the expression of SPATA12, and this expression was does-dependent. These data suggested that AP-1and Smad3/4might cooperate synergistically in regulating SPATA12promoter activity in response to TGF-β1signal. In addition, the heat shock treatment could induce the expression of SPATA12as well, which suggested that the HSF binding site in the SPATA12promoter might be responsible for heat-induction.Meanwhile, gene chip and Real-time RT-PCR were applied to study the key pathway SPATA12involed in and the results revealed that exogenous expression of SPATA12could up-regulate182genes and down regulate104genes in GC-1spg cells. Further study showed that SPATA12may delay cell cycle through down-regulating the expression of β-catenin and its target genes cyclinD1and cyclinE1, which indicates SPATA12could inhibit cell proliferation through Wnt/β-catenin signaling pathway.In conclusion, SPATA12could be regulated by AP-1, TGF-β1/Smad and heat shock in transcriptional level and it might inhibit cell proliferation through Wnt/β-catenin signaling pathway. These results provide the foundation for clarifying the regulation mechanism of SPATA12.