title: Glucosamine: fructose-6-phosphate amidotransferase in the white shrimp Litopenaeus vannamei: characterization and regulation under alkaline and cadmium stress.
abstract: Heavy metal residues and chemical contaminators considered as relevant sources of aquatic environmental pollutants have a generally immunosuppressive effect on aquatic organisms, depressing metabolic activities and immune response. Glutamine: fructose-6-phosphate aminotransferase (GFAT, EC2.6.1.16) is the first, and rate-limiting, enzyme in the hexosamine biosynthetic pathway, and is involved in the regulation of chitin biosynthesis and glycosylation of proteins. We have isolated and characterized GFAT from the white shrimp Litopenaeus vannamei. Amino acid sequence similarity of the Lv-GFAT (L.vannamei-GFAT) was highest to GFATs isolated from insects and mammals (83 % similarity to that of Haemaphysalis longicornis). The open-reading frame of the Lv-GFAT codes for a protein of 41.6 kDa with a calculated isoelectric point of 5.03. RT-PCR assays showed that endogenous Lv-GFAT mRNA is most strongly expressed in the intestine. Further analysis of Lv-GFAT gene expression in hepatopancreas by quantitative real-time PCR demonstrated that Lv-GFAT transcript levels increased when the shrimp were exposed to alkaline pH (9.3) and cadmium stress, but the time when its mRNA expression level peaked differed under these stresses. We also first expressed the recombinant protein of GFAT from shrimps in Escherichia coli. Western blot analyses confirmed that the Lv-GFAT protein was strongly expressed in the hepatopancreas after exposure to the LC-Cd stress. These results suggest that Lv-GFAT expression is stimulated by alkaline pH and cadmium stress and that it may play important roles in resistance of shrimp to environmental stresses.
authors.affiliation: Key Laboratory of Ecology and Environmental Science in Guangdong Higher Education, Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, College of Life Science, South China Normal University, Guangzhou, 510631, People's Republic of China.
authors.forename: Y
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Key Laboratory of Ecology and Environmental Science in Guangdong Higher Education, Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, College of Life Science, South China Normal University, Guangzhou, 510631, People's Republic of China.
authors.forename: D X
authors.initials: DX
authors.lastname: Cai
authors.affiliation: Key Laboratory of Ecology and Environmental Science in Guangdong Higher Education, Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, College of Life Science, South China Normal University, Guangzhou, 510631, People's Republic of China.
authors.forename: L
authors.initials: L
authors.lastname: Wang
authors.affiliation: Key Laboratory of Ecology and Environmental Science in Guangdong Higher Education, Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, College of Life Science, South China Normal University, Guangzhou, 510631, People's Republic of China.
authors.forename: J Z
authors.initials: JZ
authors.lastname: Li
authors.affiliation: Key Laboratory of Ecology and Environmental Science in Guangdong Higher Education, Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, College of Life Science, South China Normal University, Guangzhou, 510631, People's Republic of China. weina63@aliyun.com.
authors.forename: W N
authors.initials: WN
authors.lastname: Wang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D060829:Arthropod Proteins / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D002104:Cadmium / Q000633:toxicity; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D005945:Glutamine-Fructose-6-Phosphate Transaminase (Isomerizing) / Q000235:genetics* / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D033561:Penaeidae / Q000201:enzymology* / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013312:Stress, Physiological; D014874:Water Pollutants, Chemical / Q000633:toxicity
chemical_list: D060829:Arthropod Proteins; D018076:DNA, Complementary; D012333:RNA, Messenger; D014874:Water Pollutants, Chemical; D002104:Cadmium; D005945:Glutamine-Fructose-6-Phosphate Transaminase (Isomerizing)
keywords: Alkaline stress; Cadmium stress; Glucosamine: fructose-6-phosphate amidotransferase; Litopenaeus vannamei