title: Characterization of two melanin-concentrating hormone genes in zebrafish reveals evolutionary and physiological links with the mammalian MCH system.
abstract: Melanin-concentrating hormone (MCH) regulates feeding and complex behaviors in mammals and pigmentation in fish. The relationship between fish and mammalian MCH systems is not well understood. Here, we identify and characterize two MCH genes in zebrafish, Pmch1 and Pmch2. Whereas Pmch1 and its corresponding MCH1 peptide resemble MCH found in other fish, the zebrafish Pmch2 gene and MCH2 peptide share genomic structure, synteny, and high peptide sequence homology with mammalian MCH. Zebrafish Pmch genes are expressed in closely associated but non-overlapping neurons within the hypothalamus, and MCH2 neurons send numerous projections to multiple MCH receptor-rich targets with presumed roles in sensory perception, learning and memory, arousal, and homeostatic regulation. Preliminary functional analysis showed that whereas changes in zebrafish Pmch1 expression correlate with pigmentation changes, the number of MCH2-expressing neurons increases in response to chronic food deprivation. These findings demonstrate that zebrafish MCH2 is the putative structural and functional ortholog of mammalian MCH and help elucidate the nature of MCH evolution among vertebrates.
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Stanford University, Palo Alto, California 94304, USA.
authors.forename: Jennifer R
authors.initials: JR
authors.lastname: Berman
authors.forename: Gemini
authors.initials: G
authors.lastname: Skariah
authors.forename: Géraldine S
authors.initials: GS
authors.lastname: Maro
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Mignot
authors.forename: Philippe
authors.initials: P
authors.lastname: Mourrain
mesh_terms: D000818:Animals; D001483:Base Sequence; D005786:Gene Expression Regulation; D007028:Hypothalamic Hormones / Q000235:genetics* / Q000378:metabolism; D007031:Hypothalamus / Q000166:cytology / Q000378:metabolism*; D017403:In Situ Hybridization; D008543:Melanins / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D010858:Pigmentation / Q000235:genetics; D010907:Pituitary Hormones / Q000235:genetics* / Q000378:metabolism; D011979:Receptors, Pituitary Hormone / Q000235:genetics / Q000378:metabolism; D017385:Sequence Homology; D015027:Zebrafish / Q000235:genetics* / Q000378:metabolism; D029961:Zebrafish Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D007028:Hypothalamic Hormones; D008543:Melanins; D010907:Pituitary Hormones; D011979:Receptors, Pituitary Hormone; D029961:Zebrafish Proteins; C092274:melanin-concentrating hormone receptor; C019463:melanin-concentrating hormone