title: The second prolactin receptor in Nile tilapia (Oreochromis niloticus): molecular characterization, tissue distribution and gene expression.
abstract: Prolactin (PRL) is one of the most versatile hormones found in the pituitary of vertebrates and exerts its actions through binding to a specific PRL receptor (PRLR). Here we describe the cloning and characterization of a second prolactin receptor (ntPRLR2), isolated from the ovary of Nile tilapia (Oreochromis niloticus). The newly identified PRLR cDNA was 2011 bp in length and encoded 529 amino acids. It shared 31.6% identity in nucleotide sequence and 29.2% in deduced amino acid sequence with the first PRLR identified in Nile tilapia (ntPRLR1). Both of these ntPRLRs resemble the long form mammalian PRLRs. The nominated ntPRLR2 was further confirmed as a real prolactin receptor based on its competence to transactivate the beta-casein and c-fos promoters in the transiently ntPRLR2-transfected HEK293 cells. The ntPRLR2 gene also found to encode a 864-bp short form transcript in the ovary, which was confirmed by Northern blot analysis. A tissue distribution study by real-time PCR revealed that the mRNA of both receptors (ntPRLR1 and ntPRLR2) was widely expressed in different tissues, with an extremely high abundance in the osmoregulatory organs, including the gills, intestine and kidney. ntPRLR1 mRNA was more abundant than ntPRLR2 in the testis, while the reverse expression pattern was found in the ovary. In the ovary, ntPRLR2 mRNA demonstrated a distinct gonadal development-dependent expression profile, with significantly higher levels at a sexual mature stage than at sexual recrudescent and sexual regressed stages. When challenged with estradiol, ntPRLR2 mRNA expression was up-regulated by E2, whereas E2 had no significant effect on ntPRLR1.
authors.affiliation: State Key Laboratory of Biocontrol, Institute of Aquatic Economic Animals, and The Guangdong Province Key Laboratory for Aquatic Economic Animals, Sun Yat-Sen University, 510275 Guangzhou, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhang
authors.forename: Zijie
authors.initials: Z
authors.lastname: Long
authors.forename: Yangyuan
authors.initials: Y
authors.lastname: Li
authors.forename: Shibai
authors.initials: S
authors.lastname: Yi
authors.forename: Yu
authors.initials: Y
authors.lastname: Shi
authors.forename: Xilan
authors.initials: X
authors.lastname: Ma
authors.forename: Weiren
authors.initials: W
authors.lastname: Huang
authors.forename: Danqi
authors.initials: D
authors.lastname: Lu
authors.forename: Pei
authors.initials: P
authors.lastname: Zhu
authors.forename: Xiaochun
authors.initials: X
authors.lastname: Liu
authors.forename: Zining
authors.initials: Z
authors.lastname: Meng
authors.forename: Xigui
authors.initials: X
authors.lastname: Huang
authors.forename: Christopher H K
authors.initials: CH
authors.lastname: Cheng
authors.forename: Haoran
authors.initials: H
authors.lastname: Lin
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D023681:Cichlids / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D029941:Fish Proteins / Q000235:genetics* / Q000378:metabolism*; D015870:Gene Expression / Q000187:drug effects; D020869:Gene Expression Profiling; D006801:Humans; D008969:Molecular Sequence Data; D010053:Ovary / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011981:Receptors, Prolactin / Q000235:genetics* / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014018:Tissue Distribution
chemical_list: D017931:DNA Primers; D018076:DNA, Complementary; D029941:Fish Proteins; D012333:RNA, Messenger; D011981:Receptors, Prolactin; D011994:Recombinant Proteins; D004958:Estradiol