Isolation and characterization of Xenopus laevis xSox-B1 cDNA

A family of genes related to the sex-determining region Y gene (SRY) has been termed SOX, and the members are known to encode transcriptional factors and be involved in animal development. We have isolated and sequenced a novel Sox cDNA of Xenopus laevis in this study. The cDNA encodes a protein of 309 amino acids, which encompasses a B-type SOX HMG box; the cDNA was named xSox-B1 in this study. The xSox-B1 mRNA is 1.6 kb in length. Various tissues of adult frog were tested for xSox-B1 mRNA by reverse transcription/ polymerase chain reaction, and the results showed that xSox-B1 expression was highly restricted to the ovary. The message of the xSox-B1 gene was also detected in unfertilized eggs and the late blastula embryos of X. laevis. Recombinant polypeptide of the xSox-B1 HMG domain preferentially binds to the AACAAT sequence.