The human ubiquitin C-terminal hydrolase L1(UCH_L1) gene cDNA was used to search the dbEST database for homologous porcine expressed sequence tags(ESTs).A matching EST(BM194679) previous found to express Xiang pig longissimus dorsi muscle was identified.Through in silico cloning and RT-PCR with total RNA from Landrace pig longissimus dorsi muscle as the template,a(1 105 bp) cDNA fragment was amplified and subsequently sequenced.Sequence analysis revealed that this(1 105 bp) fragment contained a(669 bp) open reading frame and shared the highest homogenecitis at 91.2% and 86.5% with human and mouse homologues,respectively.The deduced peptide of 223 amino acid residues showed 96.6% homogenety to the orthologous of human and mouse,and contained a classical UCH_L1(pfam01088)domain,2 typical transmembrane domains and 3 biological-meaning sites,but with no signal peptide.Based on these characteristics this gene was nominated as pig UCH_L1 gene(GenBank(acession) number AY495532).