CDNA CLONING AND CHARACTERIZATION OF A CONSTITUTIVELY EXPRESSED ISOFORM OF THE HUMAN PEROXIN PEX11P

We cloned a human cDNA encoding an isoform of the peroxin Pex11p, term ed Pex11p beta, by screening of human liver cDNA library using as a pr obe human EST-derived, similar to 300 bp-long nucleotides showing homo logy to PEX11 from Candida boidinii and Saccharomyces cerevisiae. PEX1 1 beta encoded a protein comprising 259 amino acids, with two putative transmembrane segments, showing similar to 40% identity to inducible Pex11p alpha, at the amino acid sequence level. Pex11p beta was found to be a peroxisomal protein, as assessed by colocalization with acyl-C oA oxidase, an enzyme catalyzing the first step of peroxisomal beta-ox idation system, in Pex11p beta-expressing Chinese hamster ovary cells. PEX11 beta was not induced in rats by treatment of clofibrate, a pero xisome proliferator, in contrast to PEX11 alpha. (C) 1998 Academic Pre ss.