title: Aspartic proteases from the nematode Caenorhabditis elegans. Structural organization and developmental and cell-specific expression of asp-1.
abstract: A Caenorhabditis elegans gene (asp-1) and cDNA that encode a homologue of cathepsin D aspartic protease were cloned and characterized. The asp-1 mRNA is transcribed from a single exon, and it begins with the SL1 trans-splice leader sequence. The protein (ASP-1) is expressed as a 396-amino acid, 42.7-kDa pre-pro-peptide that is post-translationally processed into a approximately 40-kDa lysosomal protein. ASP-1 shares approximately 60% sequence identity with the aspartic protease precursor from the nematode Strongyloides stercoralis. The amino acid sequences adjacent to the two active site aspartic acid residues in ASP-1 are 100% identical to those in other eukaryotic aspartic proteases. In addition, ASP-1 contains conserved, potential disulfide bond-forming cysteine residues and N-glycosylation sites. The asp-1 gene is exclusively transcribed in the intestinal cells, with the highest levels of expression observed at late embryonic and early larval stages of development. asp-1 transcription is not observed in adult nematodes or mature larvae. Furthermore, transcription predominantly occurs in eight anterior cells of the intestine (int6-int8). Analyses of ASP-1 nucleotide and amino acid sequences revealed the presence of five additional C. elegans aspartic proteases.
authors.affiliation: Nicholas School of the Environment, Duke University, Durham, North Carolina 27708, USA.
authors.forename: I
authors.initials: I
authors.lastname: Tcherepanova
authors.forename: L
authors.initials: L
authors.lastname: Bhattacharyya
authors.forename: C S
authors.initials: CS
authors.lastname: Rubin
authors.forename: J H
authors.initials: JH
authors.lastname: Freedman
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D016282:Aspartic Acid Endopeptidases / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D001483:Base Sequence; D017173:Caenorhabditis elegans / Q000201:enzymology* / Q000235:genetics*; D002402:Cathepsin D / Q000235:genetics; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry; D018509:DNA, Helminth / Q000737:chemistry; D004792:Enzyme Precursors; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D015723:Gene Library; D017403:In Situ Hybridization; D008969:Molecular Sequence Data; D011487:Protein Conformation
chemical_list: D018076:DNA, Complementary; D018509:DNA, Helminth; D004792:Enzyme Precursors; D016282:Aspartic Acid Endopeptidases; D002402:Cathepsin D