title: Two chitin metabolic enzyme genes  from Hyriopsis cumingii: cloning,  characterization, and potential functions.
abstract: Chitin, the second most important natural polymer in  the world, and its N-deacetylated derivative chitosan are found in a wide  variety of organisms. These versatile biopolymers are associated with a broad  range of biological functions. This article is the first to report the  potential functions of 2 chitin metabolic enzyme genes from Hyriopsis  cumingii. A chitinase-3 gene (Chi-3) and a chitin deacetylase gene (Cda)  were cloned from H. cumingii and characterized. Semi-quantitative  reverse transcription polymerase chain reaction analysis revealed that the Cda gene was expressed in blood, mantle, liver, stomach, kidney, intestine,  gill, and foot, whereas Chi-3 was also expressed in those tissues but  not in blood. The tissue-specific expression of H. cumingii Chi-3 indicated  that other Chi genes may be involved in the H. cumingii immune  system. Real-time quantitative polymerase chain reaction analysis showed that  the expression of Chi-3 was significantly (P < 0.05) upregulated 12 h  after shell damage, suggesting that Chi-3 might hydrolyze superfluous  chitin after shell recovery and play a role in shell formation. Conversely, Cda expression did not change significantly (P > 0.05) to maintain a certain  degree of acetylation in chitin/chitosan. This study enriches the basic  research on chitin metabolic genes and lays foundations for further research of  shell regeneration in mussels.
authors.affiliation: Key Laboratory of Freshwater Germplasm Resources, Ministry of Agriculture, Shanghai, China.
authors.forename: G-L
authors.initials: GL
authors.lastname: Wang
authors.forename: B
authors.initials: B
authors.lastname: Xu
authors.forename: Z-Y
authors.initials: ZY
authors.lastname: Bai
authors.forename: J-L
authors.initials: JL
authors.lastname: Li
mesh_terms: D000581:Amidohydrolases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D000595:Amino Acid Sequence; D060105:Animal Shells / Q000201:enzymology; D000818:Animals; D001483:Base Sequence; D002688:Chitinases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D020224:Expressed Sequence Tags; D015870:Gene Expression; D015971:Gene Expression Regulation, Enzymologic; D008969:Molecular Sequence Data; D009928:Organ Specificity; D010802:Phylogeny; D017386:Sequence Homology, Amino Acid; D049876:Unionidae / Q000201:enzymology / Q000235:genetics*
chemical_list: D002688:Chitinases; D000581:Amidohydrolases; C019866:chitin deacetylase