CLONING OF CDNAS ENCODING PORCINE AND HUMAN DNASE-II

We report the molecular cloning of cDNAs encoding porcine and human DN ase II and the genomic structure of the human DNase II gene. The full length cDNAs for porcine and human DNase II were isolated by polymeras e chain reaction on the basis of amino acid sequences determined for t he tryptic peptides of porcine liver DNase II. The porcine and human c DNAs contain 1095 and 1083 bp open reading frames, respectively, and e ncode 364 and 360 amino acid proteins with calculated molecular masses of 40157 and 39555, respectively. The amino acid sequencing of purifi ed porcine DNase II reveals two N-termini with corresponding sequences present within the same open reading frame, suggesting proteolytic pr ocessing for the covalently bonded subunit structure of DNase II. Nort hern blot analysis demonstrated that a single transcript of 2.0 kb mRN A coding for DNase II is ubiquitously expressed in human tissues. A da tabase search revealed that the human genomic sequence of chromosome 1 93p13.2 contains the DNase II gene. Characterization of the genomic se quence showed that the DNase II gene consists of six exons separated b y five introns whose splice acceptor/donor sites agree with the GT/AG rule. (C) 1998 Academic Press.