title: Molecular cloning and gene expression analysis of the leptin receptor in the Chinese mitten crab Eriocheir sinensis.
abstract: BACKGROUND
  Leptin is an adipocyte-derived hormone with multiple functions that regulates energy homeostasis and reproductive functions. Increased knowledge of leptin receptor function will enhance our understanding of the physiological roles of leptin in animals.
  
  
  RESULTS
  In the present study, a full-length leptin receptor (lepr) cDNA, consisting of 1,353 nucleotides, was cloned from Chinese mitten crab (Eriocheir sinensis) using rapid amplification of cDNA ends (RACE) following the identification of a single expressed sequence tag (EST) clone in a cDNA library. The lepr cDNA consisted of a 22-nucleotide 5'-untranslated region (5' UTR), a 402-nucleotide open reading frame (ORF) and a 929-nucleotide 3' UTR. Multiple sequence alignments revealed that Chinese mitten crab lepr shared a conserved vacuolar protein sorting 55 (Vps55) domain with other species. Chinese mitten crab lepr expression was determined in various tissues and at three different reproductive stages using quantitative real-time RT-PCR. Lepr expression was highest in the intestine, thoracic ganglia, gonad, and accessory gonad, moderate in hepatopancreas and cranial ganglia, and low in muscle, gill, heart, haemocytes, and stomach. Furthermore, lepr expression was significantly higher in the intestine, gonad and thoracic ganglia in immature crabs relative to precocious and mature crabs. In contrast, lepr expression was significantly lower in the hepatopancreas of immature crabs relative to mature crabs.
  
  
  CONCLUSIONS
  We are the first to identify the lepr gene and to determine its gene expression patterns in various tissues and at three different reproductive stages in Chinese mitten crab. Taken together, our results suggest that lepr may be involved in the nutritional regulation of metabolism and reproduction in Chinese mitten crabs.
authors.affiliation: Department of Biology, East China Normal University, Shanghai, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Jiang
authors.forename: Fei
authors.initials: F
authors.lastname: Ren
authors.forename: Jiangling
authors.initials: J
authors.lastname: Sun
authors.forename: Lin
authors.initials: L
authors.lastname: He
authors.forename: Weiwei
authors.initials: W
authors.lastname: Li
authors.forename: Yannan
authors.initials: Y
authors.lastname: Xie
authors.forename: Qun
authors.initials: Q
authors.lastname: Wang
mesh_terms: D020121:5' Untranslated Regions; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D003445:Crustacea / Q000235:genetics*; D017931:DNA Primers; D018076:DNA, Complementary; D020869:Gene Expression Profiling; D008969:Molecular Sequence Data; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics; D054411:Receptors, Leptin / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D020121:5' Untranslated Regions; D017931:DNA Primers; D018076:DNA, Complementary; D012333:RNA, Messenger; D054411:Receptors, Leptin