We cloned cDNA encoding two peroxins, PEX-1 and PEX-6, of the nematode Caenorhabditis elegans . Peroxins are proteins that play essential roles in peroxisome biogenesis and are encoded by increasing numbers of pex genes. Among peroxins, Pex1p (yeast protein)/PEX1 (mammalian protein) and Pex6p/PEX6 constitute the subfamily 2 (SF2) of AAA proteins. SF2 presents two AAA cassettes of which the one located closest to the C-terminus is highly conserved, while the other one diverges from the consensus sequence considerably. Disorders of peroxisome biogenesis cause abnormal neuronal cell migration in brain development. This could be studied with the model organism Caenorhabditis elegans whose cell lineage has been completely established. However, none of the peroxins of this organism has been identified. In the present study we cloned cDNAs encoding two putative peroxins that belong to SF2; the genes are termed
pex-1 and
pex-6 . The length of each cDNA agreed well with the apparent size of the respective mRNA. From this and other lines of evidence we concluded both of the cDNAs to be full-length. The
pex-1 cDNA was composed of 24 exons, which were coded by a genomic region containing three ORFs,
c11h1.4,
c11h1.5, and
c11h1.6, predicted by the C. elegans Sequencing Consortium. The ORF
c11h1.5 that has a different orientation from the others was encompassed in the 15th intron of the
pex-1 cDNA. Although many exon-intron borders in
pex-1 were inconsistent with those predicted for
c11h1.4 and
c11h1.6, those in
pex-6 coincided with those for the ORF
f39g3.7. The
pex-1 and
pex-6 genes encoded proteins with 996 and 720 amino acid residues long, respectively. Both
pex-1 mRNA and
pex-6 mRNA were detectable throughout the life cycle of C. elegans , however the amount relative to that of an the egg-lying adult stage than at the embryo, L1 larva, or young adult stages. Whole-mount in situ hybridization using antisense RNA probes suggested that both
pex-1 mRNA and
pex-6 mRNA accumulated mainly in intestinal cells.