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Molecular investigation of aminopeptidase N expression in the winter flounder, Pleuronectes americanus
Author(s) -
Douglas S. E.,
Gallant J. W.,
Bullerwell C. E.
Publication year - 1999
Publication title -
journal of applied ichthyology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.392
H-Index - 62
eISSN - 1439-0426
pISSN - 0175-8659
DOI - 10.1046/j.1439-0426.1999.00117.x
Subject(s) - biology , winter flounder , flounder , complementary dna , peptide sequence , microbiology and biotechnology , protein primary structure , amino acid , conserved sequence , pleuronectes , gene , biochemistry , genetics , fishery , fish <actinopterygii>
The primary structure of a polypeptide with significant similarity to human aminopeptidase N (EC 3.4.11.2) was deduced from the sequence of two overlapping cDNA clones derived from winter flounder ( Pleuronectes americanus , Walbaum) intestinal RNA and a partial genomic clone derived from winter flounder DNA. The deduced amino acid sequence (975 amino acids) is comprised of an N‐terminal cytosolic portion of seven amino acid residues, followed by a 24‐residue transmembrane anchor region, a 38‐residue serine/threonine‐rich junction and a 906‐residue enzymatic domain that protrudes from the apical membrane of the enterocyte. A highly conserved signature sequence characteristic of zinc‐dependent metallopeptidases (HExxH) is present, as well as seven putative glycosylation sites (NxS/T). Fourteen introns are present in the 7.53 kb portion of the gene that was cloned and sequenced. Reverse transcriptase polymerase chain reaction assays using primers spanning intron/exon boundaries were used to determine the timing of expression of this gene in larval winter flounder. This represents the first aminopeptidase N sequence to be determined from a teleost fish and underscores the utility of molecular biological information in the investigation of larval fish digestion.