The appearance of proopiomelanocortin early in vertebrate evolution: cloning and sequencing of POMC from a Lamprey pituitary cDNA library.
A proopiomelanocortin (POMC)-like hormone has been cloned and sequenced from a pituitary cDNA library of upstream migrant (prespawning) sea lamprey, Petromyzon marinus. The clone, designated LPP-1, consisted of 986 nucleotides, with an open reading frame of 277 amino acids, including a signal peptide of 22 amino acids. Like POMCs from more recently evolved vertebrates, lamprey POMC contained domains which corresponded to alpha-MSH, ACTH, and beta-endorphin. However, sequences corresponding to gamma- and beta-MSH are absent or likely nonfunctional, respectively, in this cDNA. Northern blot analyses showed low but detectable expression levels of LPP-1 in larvae and strong expression in parasitic adults and prespawning animals. These observations indicate that a recognizable POMC, distinct from proenkephalin, has an ancient lineage within subphylum Vertebrata, likely dating back to the last common ancestor of the lamprey and gnathostome lines.
Heinig
J A
JA
Department of Anatomy and Cell Biology, University of Toronto, Ontario, Canada.
Keeley
F W
FW
Robson
P
P
Sower
S A
SA
Youson
J H
JH
D000324:Adrenocorticotropic Hormone / Q000737:chemistry / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D005075:Biological Evolution; D015152:Blotting, Northern; D004247:DNA / Q000032:analysis* / Q000737:chemistry / Q000235:genetics*; D007798:Lampreys / Q000235:genetics* / Q000378:metabolism; D009074:Melanocyte-Stimulating Hormones / Q000737:chemistry / Q000235:genetics; D008969:Molecular Sequence Data; D010902:Pituitary Gland / Q000737:chemistry* / Q000378:metabolism; D016133:Polymerase Chain Reaction; D011333:Pro-Opiomelanocortin / Q000032:analysis* / Q000737:chemistry / Q000235:genetics*; D012313:RNA / Q000032:analysis / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D001615:beta-Endorphin / Q000737:chemistry / Q000235:genetics
D001615:beta-Endorphin; D012313:RNA; D011333:Pro-Opiomelanocortin; D000324:Adrenocorticotropic Hormone; D009074:Melanocyte-Stimulating Hormones; D004247:DNA