title: Channel catfish, Ictalurus punctatus, cysteine proteinases: cloning, characterisation and expression of cathepsin H and L.
abstract: The antigen recognition by the host immune system is a complex biochemical process that requires a battery of enzymes. Cathepsins are one of the enzyme superfamilies involved in antigen degradation. We observed the up-regulation of catfish cathepsin H and L transcripts during the early stage of Edwardsiella ictaluri infection in preliminary studies, and speculated that cathepsin H and L may play roles in infection. We identified, sequenced and characterized the complete channel catfish cathepsin H and L cDNAs, which comprised 1415 and 1639 nucleotides, respectively. The open reading frames of cathepsin H appeared to encode a protein of 326-amino acid residues, which that of cathepsin L encoded a protein of 336 amino acids. The degree of conservation of the channel catfish cathepsin H and L amino acid sequences in comparison to other species ranged from 61% to 77%, and 67% to 85%, respectively. The catalytic triad and substrate binding sites are conserved in cathepsin H and L amino acid sequences. The cathepsin L transcript was expressed in all tissues examined, while the cathepsin H was expressed in restricted tissues. These results provide important information for further exploring the roles of channel catfish cathepsins in antigen processing.
authors.affiliation: United States Department of Agriculture, Agricultural Research Service, Aquatic Animal Health Research Unit, 990 Wire Road, Auburn, AL 36832-4352, USA. hungyueh.yeh@ars.usda.gov
authors.forename: Hung-Yueh
authors.initials: HY
authors.lastname: Yeh
authors.forename: Phillip H
authors.initials: PH
authors.lastname: Klesius
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D056655:Cathepsin H; D056668:Cathepsin L; D002403:Cathepsins / Q000737:chemistry / Q000235:genetics*; D003001:Cloning, Molecular; D003546:Cysteine Endopeptidases / Q000737:chemistry / Q000235:genetics*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D007059:Ictaluridae / Q000276:immunology / Q000502:physiology*; D008969:Molecular Sequence Data; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment
chemical_list: D002403:Cathepsins; D003546:Cysteine Endopeptidases; D056668:Cathepsin L; D056655:Cathepsin H