THE MOUSE SOX5 GENE ENCODES A PROTEIN CONTAINING THE LEUCINE-ZIPPER AND THE Q-BOX

The nucleotide sequence of mouse Sox5 (mSox5) cDNA derived from the te stis has been reported by Denny et al. (EMBO J. 11 (1992) 3705-3712). We newly isolated an mSox5 cDNA derived from 8.5-day mouse embryo. Our cDNA encodes a protein of 763 amino acids, which is considerably larg er in size than the previous one (392 amino acids) derived from the ad ult mouse testis. The most significant difference between the embryo-d erived and testis-derived mSox5 cDNAs is that the embryonic one encode s a leucine zipper motif and a neighboring glutamine-rich sequence str etch (named Q box), but the testis-derived one does not. The leucine z ipper and the Q box are highly conserved among type-D SOX proteins inc luding mSox5, mSox5 was suggested to be a single-copy gene by Southern analysis. With reverse transcription/polymerase chain reaction, we fo und that not only mouse embryo, but also the adult mouse testis, expre ss mSox5 mRNA species encoding the leucine zipper and the Q box. (C) 1 998 Elsevier Science B.V. All rights reserved.