Journal of Neuroscience, Vol 6, 2730-2735, Copyright © 1986 by Society for Neuroscience
Cloning and sequence analysis of cDNAs encoding precursors of urotensin II-alpha and -gamma
S Ohsako, I Ishida, T Ichikawa and T Deguchi
The primary structures of the precursors of urotensin II (UII)-alpha and
-gamma, neuropeptide hormones of the caudal neurosecretory system of the
carp, Cyprinus carpio, have been determined by analyzing the nucleotide
sequences of cloned DNAs complementary to the mRNAs encoding them. A cDNA
library, constructed with poly(A)+RNA in the preterminal spinal cord, was
screened using 32P-labeled synthetic oligonucleotides representing all
possible cDNA sequences corresponding to the pentapeptide common to all
forms of carp UII (UII-alpha, -beta, and - gamma). Twenty out of 39
positive clones were analyzed with the restriction endonucleases, HindIII
and PvuII, and classified into 4 groups. Nucleotide sequence analysis of 4
clones representing each group revealed that 2 clones encode the precursor
of UII-alpha and the other 2 that of UII-gamma. Both precursors consist of
125 amino acid residues, and UII-alpha and -gamma exist at the
carboxyl-termini preceded by Arg-Lys-Arg. The homology in both nucleotide
and amino acid sequences between the precursors of UII-alpha and -gamma is
more than 90%, suggesting that the genes were generated from a common
ancestral gene by duplication. There is no sequence homology between the
precursors of UII and urotensin I, another peptide hormone of the caudal
neurosecretory system, nor between the precursors of UII and
somatostatin-14. RNA transfer blot analysis indicated that mRNAs encoding
the precursors of UII-alpha and -gamma are present in the spinal cord but
not in the brain, intestine, liver, or kidney of the carp.(ABSTRACT
TRUNCATED AT 250 WORDS)