title: Characterization of duplicated heme oxygenase-1 genes and their responses to hypoxic stress in blunt snout bream (Megalobrama amblycephala).
abstract: The heme oxygenase (HO)-1 is a cytoprotective enzyme that can be involved in cytoprotection against hypoxia stress. In this study, we cloned duplicated HO-1a and HO-1b cDNAs in hypoxia-sensitive blunt snout bream (Megalobrama amblycephala). HO-1a and HO-1b encode peptides with 272 amino acids and 246 amino acids, respectively, and they share a low sequence identity of 55%. HO-1a and HO-1b mRNAs were maternally deposited in the zygote, and the mRNAs decreased to the lowest levels at 8 hpf. Both mRNAs were significantly (p < 0.01) expressed from 12 hpf and fluctuated but maintained a high level after 16 hpf. Using in situ hybridization, HO-1a and HO-1b mRNAs were ubiquitously expressed in embryos at 12 hpf. At 24 and 36 hpf, HO-1b transcripts were detected in the mid- and hindbrain, respectively, whereas HO-1a was mainly transcribed in the eyes and endoderm at 24 hpf and in the brain at 36 hpf. In adult fish, HO-1a was abundantly expressed in the heart, liver, gill, kidney, spleen, and brain, while HO-1b mRNA was detected mainly in the kidney. After exposure to hypoxic stress, both HO-1a and HO-1b mRNAs were upregulated significantly in the gill and liver but downregulated significantly in the brain (p < 0.01). These findings suggest that duplicated HO genes have evolved divergently and yet play overlapping biological roles in regulating the response to hypoxia in M. amblycephala.
authors.affiliation: Key Laboratory of Freshwater Aquatic Genetic Resources, Shanghai Ocean University, Huchenghuan Road 999, Shanghai, 201306, China.
authors.forename: Wen-Zhi
authors.initials: WZ
authors.lastname: Guan
authors.affiliation: Key Laboratory of Freshwater Aquatic Genetic Resources, Shanghai Ocean University, Huchenghuan Road 999, Shanghai, 201306, China.
authors.forename: Dan-Dan
authors.initials: DD
authors.lastname: Guo
authors.affiliation: Key Laboratory of Freshwater Aquatic Genetic Resources, Shanghai Ocean University, Huchenghuan Road 999, Shanghai, 201306, China.
authors.forename: Yi-Wen
authors.initials: YW
authors.lastname: Sun
authors.affiliation: Key Laboratory of Freshwater Aquatic Genetic Resources, Shanghai Ocean University, Huchenghuan Road 999, Shanghai, 201306, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Chen
authors.affiliation: Key Laboratory of Freshwater Aquatic Genetic Resources, Shanghai Ocean University, Huchenghuan Road 999, Shanghai, 201306, China. jiangxy@shou.edu.cn.
authors.forename: Xia-Yun
authors.initials: XY
authors.lastname: Jiang
authors.affiliation: Key Laboratory of Freshwater Aquatic Genetic Resources, Shanghai Ocean University, Huchenghuan Road 999, Shanghai, 201306, China. smzou@shou.edu.cn.
authors.forename: Shu-Ming
authors.initials: SM
authors.lastname: Zou
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D003530:Cyprinidae / Q000196:embryology / Q000235:genetics* / Q000502:physiology; D018076:DNA, Complementary / Q000235:genetics; D029941:Fish Proteins / Q000235:genetics*; D051547:Heme Oxygenase-1 / Q000235:genetics*; D000860:Hypoxia / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D013312:Stress, Physiological / Q000235:genetics*
chemical_list: D018076:DNA, Complementary; D029941:Fish Proteins; D012333:RNA, Messenger; D051547:Heme Oxygenase-1
keywords: Expression; Gene duplication; Hypoxia stress; Megalobrama amblycephala; heme oxygenase-1