title: Two isoforms of leptin in the White-clouds Mountain minnow (Tanichthys albonubes): Differential regulation by estrogen despite similar response to fasting.
abstract: Leptin has been well-established as a canonical anorexic peptide hormone in mammals, though much of its function in fish remains obscure. In this study, the cDNAs of two leptin isoforms (leptin-A and leptin-B) were cloned from the liver of a small cyprinid fish, Tanichthys albonubes. The two T. albonubes leptins, sharing low primary amino acid sequence homology with their mammalian counterparts, and between themselves, are highly conserved in three-dimensional protein structures and gene structures. Liver is a major source of leptin mRNA in T. albonubes with leptin-A being the dominant form. The expression of hepatic leptin-A but not leptin-B mRNA in female fish is significantly higher than in male fish. Transcriptional hepatic levels of leptin-A and leptin-B in both male and female fish were demonstrated to increase after long-term fasting (10-25days) but decline upon re-feeding (3days). Strikingly, estrogen (E2) administration induced only leptin-A but not leptin-B hepatic mRNA expression in both male and female fish. Our study here provides the first evidence for differential regulation of two leptins in fish, and sheds new light on the possible origin of leptin in lower vertebrates.
authors.affiliation: CAS Key Laboratory of Tropical Marine Bio-resources and Ecology (LMB), Guangdong Provincial Key Laboratory of Applied Marine Biology (LAMB), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China; South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, Guangzhou, China. Electronic address: chan1010@scsio.ac.cn.
authors.forename: Ting
authors.initials: T
authors.lastname: Chen
authors.affiliation: Department of Anatomy, University of Hong Kong, Hong Kong, China. Electronic address: chenss@hku.hk.
authors.forename: Shuang
authors.initials: S
authors.lastname: Chen
authors.affiliation: CAS Key Laboratory of Tropical Marine Bio-resources and Ecology (LMB), Guangdong Provincial Key Laboratory of Applied Marine Biology (LAMB), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China; South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, Guangzhou, China. Electronic address: rosemary166@sina.com.
authors.forename: Chunhua
authors.initials: C
authors.lastname: Ren
authors.affiliation: CAS Key Laboratory of Tropical Marine Bio-resources and Ecology (LMB), Guangdong Provincial Key Laboratory of Applied Marine Biology (LAMB), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China; South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, Guangzhou, China. Electronic address: hucq@scsio.ac.cn.
authors.forename: Chaoqun
authors.initials: C
authors.lastname: Hu
authors.affiliation: College of Medicine, Foshan University, Foshan, China. Electronic address: tangdsh@163.com.
authors.forename: Dongsheng
authors.initials: D
authors.lastname: Tang
authors.affiliation: College of Medicine, Foshan University, Foshan, China. Electronic address: yanaifen@mail3.sysu.edu.cn.
authors.forename: Aifen
authors.initials: A
authors.lastname: Yan
mesh_terms: D000818:Animals; D001483:Base Sequence; D003530:Cyprinidae / Q000378:metabolism*; D018076:DNA, Complementary / Q000235:genetics; D004958:Estradiol / Q000494:pharmacology*; D005215:Fasting / Q000378:metabolism; D005260:Female; D020738:Leptin / Q000378:metabolism*; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D020033:Protein Isoforms / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D012727:Sex Characteristics
chemical_list: D018076:DNA, Complementary; D020738:Leptin; D020033:Protein Isoforms; D012333:RNA, Messenger; D004958:Estradiol
keywords: Cyprinid fish; Estrogen; Fasting; Gene expression; Leptin; Molecular cloning