Characterization of a cDNA encoding a novel avian hypothalamic neuropeptide exerting an inhibitory effect on gonadotropin release

Satake, H Hisada, M Kawada, T Minakata, H Ukena, K Tsutsui, K

H. Satake et al., Characterization of a cDNA encoding a novel avian hypothalamic neuropeptide exerting an inhibitory effect on gonadotropin release, BIOCHEM J, 354, 2001, pp. 379-385

35

INGLESE

Article

Biochemistry & Biophysics

BIOCHEMICAL JOURNAL

0264-6021 → ACNP

354

2001

2

379 - 385

ISI

0264-6021(20010301)354:<379:COACEA>2.0.ZU;2-N

We previously isolated a novel dodecapeptide containing a C-terminal -Arg-P he-NH2 sequence, SIKPSAYLPLRF-NH2 (RFamide peptide), from the quail brain. This quail RFamide peptide was shown to decrease gonadotropin release from the cultured anterior pituitary and to be located at least in the quail hyp othalamo-hypophysial system. We therefore designated this RFamide peptide g onadotropin inhibitory hormone (GnIH). In the present study we characterize d the GnIH cDNA from the quail brain by a combination of 3' and 5' rapid am plification of cDNA. ends ('RACE'). The deduced GnIH precursor consisted of 173 amino acid residues, encoding one GnIH and two putative gene-related p eptide (GnIH-RP-1 and GnIH-RP-2) sequences that included -LPXRF (X = L or Q ) at their C-termini. All these peptide sequences were flanked by a glycine C-terminal amidation signal and a single basic amino acid on each end as a n endoproteolytic site. Southern blotting analysis of reverse-transcriptase -mediated PCR products demonstrated a specific expression of the gene encod ing GnIH in the diencephalon including the hypothalamus. Furthermore, mass spectrometric analyses detected the mass numbers for matured GnIH and GnIH- RP-2, revealing that both peptides are produced from the precursor in the d iencephalon as an endogenous ligand. Taken together, these results lead to the conclusion that GnIH is a hypothalamic factor responsible for the negat ive regulation of gonadotropin secretion. Furthermore, the presence of a no vel RFamide peptide family containing a C-terminal -LPXRF-NH2 sequence has been revealed.