RESUMO
<p><b>OBJECTIVE</b>To clone the full-length Rcet3 gene, a novel gene related to family 2 cystatins, from mouse testis or other tissues.</p><p><b>METHODS</b>Rcet3 gene was cloned using digital differential display (DDD) and RT-PCR was performed for cloning the full-length Rcet3 gene from adult mouse testis cDNA library with sequence analysis.</p><p><b>RESULTS</b>Rcet3 cDNA was 610 bp in length, consisting of 4 exons to encode a protein with 140 amino acid residues. The encoded protein contained a potential signal peptide and a cystatin domain, but lacked critical consensus site important for cysteine protease inhibition. These characteristics could be seen in the Cres subgroup related to the family 2 cystatins. Rcet3 was specifically expressed in adult mouse testis, epididymis and the cerebrum, but at higher levels in the testis than in the epididymis and cerebrum.</p><p><b>CONCLUSION</b>Rcet3 may be a new member of Cres subgroup of family 2 cystatins.</p>