Cloning of the cDNA encoding the urotensin II precursor in frog and human reveals intense expression of the urotensin II gene in motoneurons of the spinal cord

Abstract

Urotensin II (UII) is a cyclic peptide initially isolated from the caudal neurosecretory system of teleost fish. Subsequently, UII has been characterized from a frog brain extract, indicating that a gene encoding a UII precursor is also present in the genome of a tetrapod. Here, we report the characterization of the cDNAs encoding frog and human UII precursors and the localization of the corresponding mRNAs. In both frog and human, the UII sequence is located at the C-terminal position of the precursor. Human UII is composed of only 11 amino acid residues, while fish and frog UII possess 12 and 13 amino acid residues, respectively. The cyclic region of UII, which is responsible for the biological activity of the peptide, has been fully conserved from fish to human. Northern blot and dot blot analysis revealed that UII precursor mRNAs are found predominantly in the frog and human spinal cord. In situ hybridization studies showed that the UII precursor gene is actively expressed in motoneurons. The present study demonstrates that UII, which has long been regarded as a peptide exclusively produced by the urophysis of teleost fish, is actually present in the brain of amphibians and mammals. The fact that evolutionary pressure has acted to conserve fully the biologically active sequence of UII suggests that the peptide may exert important physiological functions in humans.

Differential vasoconstrictor activity of human urotensin‐II in vascular tissue isolated from the rat, mouse, dog, pig, marmoset and cynomolgus monkey

“…Since evolutionary pressure has acted to conserve this isopeptide family across a diverse range of species, it has been proposed that this peptide family exerts similar physiological actions in higher species including mammals. This hypothesis is supported by the recent identi®cation of U-II isopeptides in the rat, mouse, pig and man (Ames et al, 1999;Coulouarn et al, 1998;Mori et al, 1999). The present study has evaluated the functional activity of human U-II in a range of native vascular tissue isolated from a variety of mammals.…”

“…Indeed, rp-HPLC fractions of porcine spinal cord, bovine hypothalamic and squirrel monkey brain extracts selectively activate GPR14 (Mori et al, 1999;Nothacker et al, 1999). However, in addition to the CNS, U-II is clearly present within the mammalian periphery including the vasculature (cardiac myocytes, coronary atheroma; Ames et al, 1999) and several other peripheral tissues including kidney, adrenal gland, pancreas and liver (Coulouarn et al, 1998;Nothacker et al, 1999). Further, in addition to any putative paracrine action, U-II likely functions as an endocrine factor since U-II-like immunoreactivity has been detected within ®sh plasma (*30 pM; Kobayashi et al, 1986;Winter et al, 1999).…”

“…The cloning of the vasoactive cyclic undecapeptide human Urotensin-II (U-II), a selective ligand for the novel serpentine seven transmembrane receptor, GPR14 (Ames et al, 1999), is one such pairing that has met with considerable interest recently (Hare et al, 1999;Davenport & Maguire, 2000;Newby & Jalan, 2000;Gray et al, 2000) since (a) human U-II and GPR14 are both expressed within the vasculature and (b) preliminary pharmacological evaluation indicates that human U-II possesses signi®cant vasoactive properties (Ames et al, 1999;Bottrill et al, 2000;MacLean et al, 2000).GPR14 (Mori et al, 1999;Nothacker et al, 1999). However, in addition to the CNS, U-II is clearly present within the mammalian periphery including the vasculature (cardiac myocytes, coronary atheroma; Ames et al, 1999) and several other peripheral tissues including kidney, adrenal gland, pancreas and liver (Coulouarn et al, 1998;Nothacker et al, 1999). Further, in addition to any putative paracrine action, U-II likely functions as an endocrine factor since U-II-like immunoreactivity has been detected within ®sh plasma (*30 pM; Kobayashi et al, 1986;Winter et al, 1999).…”

“…The cloning of the vasoactive cyclic undecapeptide human Urotensin-II (U-II), a selective ligand for the novel serpentine seven transmembrane receptor, GPR14 (Ames et al, 1999), is one such pairing that has met with considerable interest recently (Hare et al, 1999;Davenport & Maguire, 2000;Newby & Jalan, 2000;Gray et al, 2000) since (a) human U-II and GPR14 are both expressed within the vasculature and (b) preliminary pharmacological evaluation indicates that human U-II possesses signi®cant vasoactive properties (Ames et al, 1999;Bottrill et al, 2000;MacLean et al, 2000). PreproU-II mRNA is expressed abundantly within the CNS of frogs, rats and humans (medulla oblongata, acetylcholinesterase-positive ventral horn motor neurones; Coulouarn et al, 1998;Ames et al, 1999). Indeed, rp-HPLC fractions of porcine spinal cord, bovine hypothalamic and squirrel monkey brain extracts selectively activate GPR14 (Mori et al, 1999;Nothacker et al, 1999).…”

Où l’on apprend comment la grenouille pourrait se faire aussi grosse que le boeuf…

“…La pertinence de cette approche comparative avait déjà été validée avec la découverte de la sécrétoneurine [7], de la cortistatine [8] et de l'urotensine II [9] chez l'homme, trois neuropeptides initialement isolés à partir du cerveau de la grenouille [10][11][12]. Afin de rechercher de nouveaux membres de la famille des peptides RFamide chez les vertébrés, les chercheurs rouennais ont criblé des fractions pré-purifiées d'un extrait de cerveaux de grenouille à l'aide d'un anticorps dirigé contre le motif Arg-Phe-NH 2 .…”