Isolation and Characterization ofXenopus laevis xSox-B1cDNA

A family of genes related to the sex-determining region Y gene (SRY) has been termedSOX,and the members are known to encode transcriptional factors and be involved in animal development. We have isolated and sequenced a novelSoxcDNA ofXenopus laevisin this study. The cDNA encodes a protein of 309 amino acids, which encompasses a B-type SOX HMG box; the cDNA was namedxSox-B1in this study. ThexSox-B1mRNA is 1.6 kb in length. Various tissues of adult frog were tested forxSox-B1mRNA by reverse transcription/ polymerase chain reaction, and the results showed thatxSox-B1expression was highly restricted to the ovary. The message of thexSox-B1gene was also detected in unfertilized eggs and the late blastula embryos ofX. laevis.Recombinant polypeptide of the xSox-B1 HMG domain preferentially binds to the AACAAT sequence.