title: Identification and expression of a novel carbonic anhydrase isozyme in the pufferfish Takifugu vermicularis.
abstract: Carbonic anhydrase (CA) is a key element for maintaining acid base balance in fish. In our present experiment, novel CA isozymes were identified from the pear puffer (Takifugu vermicularis). Based on the high homology of two predicted CA sequences of the tiger puffer (Takifugu rubripes), a 1715bp novel cDNA was obtained from T. vermicularis. The open reading frame showed a complete coding sequence of 552bp with a deduced peptide sequence of 183 amino acids that exhibited highest (97%) identity with pufferfish putative CA III and CA IV-like sequences. In addition, this translated protein sequence showed 36-37% identity with zebrafish CA IV-like, CA XVa, CA XVb, and CA XVc proteins. Phylogenetic analysis revealed that the pufferfish novel protein (pCAn) was a membrane-bound CA protein. Alignment of multiple CA sequences illustrated that most of the putative active site residues of the pCAn isozyme were situated at highly conserved regions of the CA sequences. Examination of motif distribution suggested that the pCAn isozyme was very similar to the puffer predicted CA IV-like isozyme. Reverse transcription-polymerase chain reaction (PCR) analysis showed highly differential expression in the brain, gills, kidney, and muscle, whereas CA mRNA expression was almost absent in heart, liver, and intestine. Quantitative PCR expression of CA mRNA abundance suggested several-fold higher expression of pCAn isozymes in the gills compared to other tissues tested. Our results suggest that the pCAn isozyme might be related to CA IV-like isozymes. Further functional studies are needed to investigate the function of the pCAn isozyme in T. vermicularis.
authors.affiliation: Department of Fisheries Science, College of Fisheries and Ocean Sciences, Chonnam National University, 50, Daehak-ro, Yeosu, Jeonnam 59626, Republic of Korea. Electronic address: krsumi@pstu.ac.bd.
authors.forename: Kanij Rukshana
authors.initials: KR
authors.lastname: Sumi
authors.affiliation: Department of Horticulture, College of Life Science and Natural Resources, Sunchon National University, 255, Jungang-ro, Suncheon-Si, Jeollanam-do, 67922, Republic of Korea. Electronic address: nis@sunchon.ac.kr.
authors.forename: Ill-Sup
authors.initials: IS
authors.lastname: Nou
authors.affiliation: Department of Fisheries Science, College of Fisheries and Ocean Sciences, Chonnam National University, 50, Daehak-ro, Yeosu, Jeonnam 59626, Republic of Korea. Electronic address: kkh@chonnam.ac.kr.
authors.forename: Kang Hee
authors.initials: KH
authors.lastname: Kho
mesh_terms: D000136:Acid-Base Equilibrium; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000201:enzymology; D002256:Carbonic Anhydrases / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D029941:Fish Proteins / Q000235:genetics* / Q000378:metabolism; D015870:Gene Expression; D005880:Gills / Q000737:chemistry / Q000201:enzymology*; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D007668:Kidney / Q000737:chemistry / Q000201:enzymology; D009132:Muscles / Q000737:chemistry / Q000201:enzymology; D016366:Open Reading Frames; D010802:Phylogeny; D060888:Real-Time Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D023741:Takifugu / Q000145:classification / Q000235:genetics* / Q000378:metabolism
chemical_list: D018076:DNA, Complementary; D029941:Fish Proteins; D007527:Isoenzymes; D011994:Recombinant Proteins; D002256:Carbonic Anhydrases
keywords: Carbonic anhydrase isozyme; Gills; Pufferfish