A possible role of STRA8 as a transcriptional factor

The Stra8 gene is a retinoic acid responsive gene. Its expression in premeiotic germ cells in both sexes implies that STRA8 protein plays roles for the progression of meiosis. Stra8 deficient germ cells do not initiate meiotic chromosome condensation and DNA double strand breaks. Its deficient mice were infertile. STRA8 is required for the transition into meiosis in both female and male germ cells. In addition its expression was confirmed in trophoblast giant cells in placenta, indicating another physiological role of STRA8 in other tissues. Yet it is still unclear how STRA8 is related in molecular level to meiosis and placentation. Here we report a possible function of STRA8 as a transcription factor. We have discovered that Stra8 gene is present in the nucleus and can activate basal transcription in F9 and P19 cells. Deletion mutant study revealed that C-terminus of STRA8 protein is important for its transcriptional activation activity. And N-terminus of the protein is critical for its nucleus localization. Moreover, random oligonucleotide electrophoresis mobility shift assay shows that the STRA8 directly binds to double strand DNA.