title: Duplication and differentiation of common carp (Cyprinus carpio) myoglobin genes revealed by BAC analysis.
abstract: Two distinct myoglobin (mb) transcripts have been reported in common carp, Cyprinus carpio, which is a hypoxia-tolerant fish living in habitats with greatly fluctuant dissolved oxygen levels. Recombinant protein analysis has shown functional specialization of the two mb transcripts. In this work, analysis for mb-containing bacterial artificial chromosome (BAC) clones indicated different genome loci for common carp myoglobin-1 (mb-1) and myoglobin-2 (mb-2) genes. Fluorescence in situ hybridization (FISH) revealed that mb-1 and mb-2 are located on separate chromosomes. In both of the mb-1 and mb-2 containing BAC clones, gene synteny was well conserved with the homologous region on zebrafish chromosome 1, supporting that the common carp specific mb-2 gene originated from the recent whole genome duplication event in cyprinid lineage. Transcription factor binding sites search indicated that both common carp mb genes lacked specificity Protein 1 (Sp1) and myocyte enhancer factor-2 (MEF2) binding sites, which mediated muscle-specific and calcium-dependent expression in the well-studied mb promoters. Potential hypoxia response elements (HREs) were predicted in the regulatory region of common carp mb genes. These characteristics of common carp mb gene regulatory region well interpreted the hypoxia-inducible, non-muscle expression pattern of mb-1. In the case of mb-2, a 10 bp insertion to the binding site of upstream stimulatory factor (USF), which was a co-factor of hypoxia inducible factor (HIF), might cause the non-response to hypoxia treatment of mb-2. The case of common carp mb gene duplication and subsequent differentiation in expression pattern and protein function provided an example for adaptive evolution toward aquatic hypoxia tolerance.
authors.affiliation: The Center for Applied Aquatic Genomics, Chinese Academy of Fishery Sciences, Beijing 100141, PR China.
authors.forename: Zi-Xia
authors.initials: ZX
authors.lastname: Zhao
authors.affiliation: The Center for Applied Aquatic Genomics, Chinese Academy of Fishery Sciences, Beijing 100141, PR China.
authors.forename: Peng
authors.initials: P
authors.lastname: Xu
authors.affiliation: Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin 150070, PR China.
authors.forename: Ding-Chen
authors.initials: DC
authors.lastname: Cao
authors.affiliation: Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin 150070, PR China.
authors.forename: You-Yi
authors.initials: YY
authors.lastname: Kuang
authors.affiliation: The Center for Applied Aquatic Genomics, Chinese Academy of Fishery Sciences, Beijing 100141, PR China.
authors.forename: Hai-Xia
authors.initials: HX
authors.lastname: Deng
authors.affiliation: The Center for Applied Aquatic Genomics, Chinese Academy of Fishery Sciences, Beijing 100141, PR China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: The Center for Applied Aquatic Genomics, Chinese Academy of Fishery Sciences, Beijing 100141, PR China.
authors.forename: Li-Ming
authors.initials: LM
authors.lastname: Xu
authors.affiliation: The Center for Applied Aquatic Genomics, Chinese Academy of Fishery Sciences, Beijing 100141, PR China.
authors.forename: Jiong-Tang
authors.initials: JT
authors.lastname: Li
authors.affiliation: The Center for Applied Aquatic Genomics, Chinese Academy of Fishery Sciences, Beijing 100141, PR China.
authors.forename: Jian
authors.initials: J
authors.lastname: Xu
authors.affiliation: The Center for Applied Aquatic Genomics, Chinese Academy of Fishery Sciences, Beijing 100141, PR China; Heilongjiang River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Harbin 150070, PR China. Electronic address: sunxw2002@163.com.
authors.forename: Xiao-Wen
authors.initials: XW
authors.lastname: Sun
mesh_terms: D000818:Animals; D001665:Binding Sites / Q000502:physiology; D002347:Carps / Q000235:genetics*; D015687:Cell Hypoxia / Q000235:genetics / Q000502:physiology; D002875:Chromosomes; D022202:Chromosomes, Artificial, Bacterial / Q000235:genetics; D003530:Cyprinidae / Q000235:genetics; D019143:Evolution, Molecular; D029941:Fish Proteins / Q000235:genetics* / Q000378:metabolism; D020440:Gene Duplication; D049810:Genetic Speciation; D016678:Genome; D009211:Myoglobin / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D026801:Synteny; D015027:Zebrafish / Q000235:genetics
chemical_list: D029941:Fish Proteins; D009211:Myoglobin
keywords: Common carp; Differentiation; Duplication; Hypoxia; Myoglobin