Molecular cloning of lungfish proopiomelanocortin cDNA.
To investigate the evolution of proopiomelanocortin (POMC) from fish to tetrapods, nucleotide sequence of POMC cDNA from a lobe-finned fish, the African lungfish, was determined. POMC cDNA was prepared from lungfish pituitary glands. The POMC cDNA is composed of 1114 bp, excluding a poly-A tail, and encodes 255 amino acids (aa) including a signal peptide of 25 aa. The lungfish POMC contains the segment corresponding to gamma-melanotropin (MSH), corticotropin, alpha-MSH, beta-MSH, and beta-endorphin at positions (50-61), (108-146), (108-120), (178-194), and (197-230), respectively. The lungfish POMC shows greater sequence identity on average with amphibian (62%), ancient ray-finned fishes including acipenseriformes and semionotiformes (62%), and mammalian POMC (52%) than with teleostean (49%), elasmobranch (46%), and agnathan POMC (31%). Thus, the overall structural feature of lungfish POMC is close to the tetrapod POMCs which contain gamma-MSH and the ancient ray-finned fishes POMCs containing gamma-MSH-like sequence. However, amino acid sequence of lungfish beta-endorphin exhibits properties which are specifically observed in the ray-finned fishes and the elasmobranchs.
Amemiya
Y
Y
School of Fisheries Sciences, Kitasato University, Iwate, Sanriku, 022-0101, Japan.
Takahashi
A
A
Meguro
H
H
Kawauchi
H
H
D000324:Adrenocorticotropic Hormone / Q000737:chemistry; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D019143:Evolution, Molecular; D005399:Fishes / Q000235:genetics*; D008969:Molecular Sequence Data; D010902:Pituitary Gland / Q000737:chemistry; D011333:Pro-Opiomelanocortin / Q000737:chemistry / Q000235:genetics*; D021382:Protein Sorting Signals / Q000737:chemistry / Q000235:genetics; D000521:alpha-MSH / Q000737:chemistry; D001615:beta-Endorphin / Q000737:chemistry; D019824:beta-MSH / Q000737:chemistry; D019825:gamma-MSH / Q000737:chemistry
D018076:DNA, Complementary; D021382:Protein Sorting Signals; D019824:beta-MSH; D019825:gamma-MSH; D000521:alpha-MSH; D001615:beta-Endorphin; D011333:Pro-Opiomelanocortin; D000324:Adrenocorticotropic Hormone