Structure and distribution of the mRNAs encoding pituitary adenylate cyclase-activating polypeptide and growth hormone-releasing hormone-like peptide in the frog, Rana ridibunda.
The structure of the neuropeptide pituitary adenylate cyclase-activating polypeptide (PACAP) has been characterized in several species including protochordates, fish, amphibians, birds, and mammals. Although PACAP has been shown to stimulate frog pituitary and adrenal cell activity, the structure of the PACAP precursor and the expression of its gene have not yet been reported in any amphibian species. In this study, we have characterized two cDNA variants encoding PACAP of the frog Rana ridibunda, one of which encodes a second peptide exhibiting strong homologies to growth hormone-releasing hormone (GHRH) of fish and mammals. Northern blot and reverse transcriptase-polymerase chain reaction (RT-PCR) analyses revealed that PACAP/GHRH-like peptide mRNAs are predominantly expressed in the brain and spinal cord and, to a lesser extent, in the neurointermediate lobe of the pituitary. Other tissues including the testis and the distal lobe of the pituitary do not express the PACAP precursor gene. The distribution of PACAP/GHRH-like peptide mRNAs in the frog brain has been determined by in situ hybridization histochemistry. High levels of expression were found in the accessory olfactory bulb, the distal pallium, the ventral part of the magnocellular preoptic nucleus, the ventral hypothalamic nucleus, the posterior tuberculum, and the ventral habenular nucleus. These data contribute to the understanding of the evolution of the PACAP and GHRH genes in vertebrates and provide the anatomical bases to elucidate the roles of PACAP and the GHRH-like peptide in amphibians.
Alexandre
D
D
European Institute for Peptide Research (IFRMP 23), Laboratory of Cellular and Molecular Neuroendocrinology, INSERM U413, UA CNRS, University of Rouen, 76821 Mont-Saint-Aignan, France.
Vaudry
H
H
Jégou
S
S
Anouar
Y
Y
D000595:Amino Acid Sequence / Q000235:genetics; D000818:Animals; D001483:Base Sequence / Q000235:genetics; D001921:Brain / Q000378:metabolism; D018076:DNA, Complementary / Q000737:chemistry; D015870:Gene Expression / Q000235:genetics*; D013007:Growth Hormone-Releasing Hormone / Q000235:genetics* / Q000378:metabolism; D008297:Male; D008969:Molecular Sequence Data; D009479:Neuropeptides / Q000235:genetics*; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D010902:Pituitary Gland / Q000378:metabolism*; D012322:RNA Precursors / Q000737:chemistry*; D011895:Rana ridibunda / Q000235:genetics* / Q000378:metabolism; D013116:Spinal Cord / Q000378:metabolism
D018076:DNA, Complementary; D009479:Neuropeptides; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D012322:RNA Precursors; C099166:growth hormone releasing hormone-related peptide; D013007:Growth Hormone-Releasing Hormone