Comparative genomics provides evidence for close evolutionary relationships between the urotensin II and somatostatin gene families.
Although urotensin II (UII) and somatostatin 1 (SS1) exhibit some structural similarities, their precursors do not show any appreciable sequence identity and, thus, it is widely accepted that the UII and SS1 genes do not derive from a common ancestral gene. The recent characterization of novel isoforms of these two peptides, namely urotensin II-related peptide (URP) and somatostatin 2 (SS2)/cortistatin (CST), provides new opportunity to revisit the phylogenetic relationships of UII and SS1 using a comparative genomics approach. In the present study, by radiation hybrid mapping and in silico sequence analysis, we have determined the chromosomal localization of the genes encoding UII- and somatostatin-related peptides in several vertebrate species, including human, chicken, and zebrafish. In most of the species investigated, the UII and URP genes are closely linked to the SS2/CST and SS1 genes, respectively. We also found that the UII-SS2/CST locus and the URP/SS1 locus are paralogous. Taken together, these data indicate that the UII and URP genes, on the one hand, and the SS1 and SS2/CST genes, on the other hand, arose through a segmental duplication of two ancestral genes that were already physically linked to each other. Our results also suggest that these two genes arose themselves through a tandem duplication of a single ancestral gene. It thus appears that the genes encoding UII- and somatostatin-related peptides belong to the same superfamily.
Tostivint
Hervé
H
Institut National de la Santé et de la Recherche Médicale Unité 413, Laboratory of Cellular and Molecular Neuroendocrinology, European Institute for Peptide Research, University of Rouen, 76821 Mont-Saint-Aignan, France.
Joly
Lucille
L
Lihrmann
Isabelle
I
Parmentier
Caroline
C
Lebon
Alexis
A
Morisson
Mireille
M
Calas
André
A
Ekker
Marc
M
Vaudry
Hubert
H
D000595:Amino Acid Sequence; D000818:Animals; D002645:Chickens; D002874:Chromosome Mapping; D002878:Chromosomes, Human, Pair 1 / Q000235:genetics; D002893:Chromosomes, Human, Pair 3 / Q000235:genetics; D019143:Evolution, Molecular; D020440:Gene Duplication; D005796:Genes / Q000235:genetics; D023281:Genomics; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry / Q000235:genetics; D010802:Phylogeny; D051381:Rats; D013004:Somatostatin / Q000737:chemistry / Q000145:classification* / Q000235:genetics*; D014579:Urotensins / Q000737:chemistry / Q000145:classification* / Q000235:genetics*; D015027:Zebrafish
D010455:Peptides; D014579:Urotensins; D013004:Somatostatin; C029677:urotensin II