tailieunhanh - Báo cáo khoa học: Isolation, characterization and expression analysis of a hypoxia-responsive glucose transporter gene from the grass carp, Ctenopharyngodon idellus

Glucose transporters (GLUTs) have been implicated in adaptive and survival responses to hypoxic stress in mam-mals. In fish, the expression and regulation ofGLUT in relation to hypoxia remains unexplored. Here we describe the identification ofa hypoxia-responsive glucose transpor-ter gene (gcGLUT) and the corresponding full-length cDNA from the grass carp. The gene spans 11 kb ofgenomic sequence and consists of12 exons and 11 introns, and an open reading frame (ORF) of 1599 bp encoding a poly-peptide of533 amino acids, with a predictedmolecularmass of 57 kDa and a pI | Eur. J. Biochem. 270 3010-3017 2003 FEBS 2003 doi Isolation characterization and expression analysis of a hypoxia-responsive glucose transporter gene from the grass carp Ctenopharyngodon idellus Ziping Zhang Rudolf S. S. Wu Helen O. L. Mok Yilei Wang Winnie W. L. Poon Shuk H. Cheng and Richard Y. C. Kong Department of Biology and Chemistry and Centre for Coastal Pollution and Conservation City University of Hong Kong Kowloon Tong Hong Kong Special Administrative Region People s Republic of China Glucose transporters GLUTs have been implicated in adaptive and survival responses to hypoxic stress in mammals. In fish the expression and regulation of GLUT in relation to hypoxia remains unexplored. Here we describe the identification ofa hypoxia-responsive glucose transporter gene gcGLUT and the corresponding full-length cDNA from the grass carp. The gene spans w 11 kb of genomic sequence and consists of 12 exons and 11 mtrons nidi an open reading frame ORF of 1599 bp encoding a polypeptide of 5 á 3 amino acids. with a pi edícted molecular mass of w 57 kDa and a pl of . BLASTX analysis showed that the ORF shared high sequence identity with the GLUT1 57-59 GLUT3 59-60 and GlUt4 55-59 proteins from different vertebrates. Comparative analysis of GLUT genomic structures showed that the arrangement of exons and position ofsplit codons are highly conserved amongst members ofthe class I GLUTs suggesting that these genes share a common ancestor. Phylogenetic analysis indicated that gcGLUT is most closely related to the GLUT3 proteins. Northern blot analysis showed that the gcGLUT transcript was most abundantly expressed and responsive to hypoxia in kidney. Up-regulated expression by hypoxia was also evident in eye and gill but differential patterns ofexpression were observed. Low expression levels detected in brain heart liver and muscle were not responsive to hypoxic stress. Keywords Ctenopharyngodon idellus glucose transporter grass