RESUMO
A relaxin-like gonad-stimulating peptide (RGP) in starfish was the first identified invertebrate gonadotropin responsible for final gamete maturation. An RGP ortholog was newly identified from Astropecten scoparius of the order Paxillosida. The A. scoparius RGP (AscRGP) precursor is encoded by a 354 base pair open reading frame and is a 118 amino acid (aa) protein consisting of a signal peptide (26 aa), B-chain (21 aa), C-peptide (47 aa), and A-chain (24 aa). There are three putative processing sites (Lys-Arg) between the B-chain and C-peptide, between the C-peptide and A-chain, and within the C-peptide. This structural organization revealed that the mature AscRGP is composed of A- and B-chains with two interchain disulfide bonds and one intrachain disulfide bond. The C-terminal residues of the B-chain are Gln-Gly-Arg, which is a potential substrate for formation of an amidated C-terminal Gln residue. Non-amidated (AscRGP-GR) and amidated (AscRGP-NH2 ) peptides were chemically synthesized and their effect on gamete shedding activity was examined using A. scoparius ovaries. Both AscRGP-GR and AscRGP-NH2 induced oocyte maturation and ovulation in similar dose-dependent manners. This is the first report on a C-terminally amidated functional RGP. Collectively, these results suggest that AscRGP-GR and AscRGP-NH2 act as a natural gonadotropic hormone in A. scoparius.
Assuntos
Gonadotropinas/química , Gonadotropinas/metabolismo , Hormônios de Invertebrado/química , Hormônios de Invertebrado/metabolismo , Neuropeptídeos/química , Neuropeptídeos/metabolismo , Oócitos/metabolismo , Ovário/metabolismo , Estrelas-do-Mar/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Células Cultivadas , Feminino , Gonadotropinas/síntese química , Gonadotropinas/farmacologia , Hormônios de Invertebrado/síntese química , Hormônios de Invertebrado/farmacologia , Neuropeptídeos/síntese química , Neuropeptídeos/farmacologia , Oócitos/efeitos dos fármacos , Oogênese/efeitos dos fármacos , Ovário/efeitos dos fármacos , Ovulação/efeitos dos fármacos , Filogenia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Nervo Radial/metabolismo , Estrelas-do-Mar/efeitos dos fármacos , Estrelas-do-Mar/genéticaRESUMO
The gonadotropin hormone family is distinguished by its heterodimeric structure in which the members share a common alpha subunit and a hormone-specific beta subunit. Since assembly of the heterodimer is often the rate-limiting step in production of functional hormone, single-chain hormones have been engineered by genetically linking the two subunits. The single-chain hormone can in turn be fused to its receptor to produce a functional single-chain hormone-receptor complex. These fusion constructs offer a valuable new approach in structure-function studies and in the generation of hormone analogs. In this article we describe the experimental design for the generation of single-chain human chorionic gonadotropin and single-chain hormone-receptor fusion complex and strategies for the expression of these fusion proteins.
Assuntos
Engenharia Genética/métodos , Gonadotropinas/síntese química , Gonadotropinas/genética , Receptores da Gonadotropina/genética , Proteínas Recombinantes de Fusão/genética , Sequência de Aminoácidos , Animais , Células COS , Linhagem Celular , Gonadotropina Coriônica/química , Gonadotropina Coriônica/genética , AMP Cíclico/biossíntese , Humanos , Dados de Sequência Molecular , Peptídeos/metabolismo , Proteínas Recombinantes de Fusão/metabolismo , TransfecçãoRESUMO
An original insect neurohormone of 65 residues was synthesized by the solid-phase methodology using t-Boc strategy and Boc-Val-PAM-resin. The purification, conducted by several steps of liquid chromatography having mass, polarity or charge as separative criteria, yielded the product with the correct molecular weight of 6922 Da determined by mass spectrometry. The synthetic peptide had both the same affinity for the anti-native neurohormone serum and the same biological activity as the native neurohormone.
Assuntos
Gonadotropinas/síntese química , Hormônios de Inseto/síntese química , Proteínas de Insetos/síntese química , Proteínas do Tecido Nervoso/síntese química , Sequência de Aminoácidos , Animais , Feminino , Gonadotropinas/isolamento & purificação , Gonadotropinas/farmacologia , Gafanhotos , Imunoquímica , Hormônios de Inseto/isolamento & purificação , Hormônios de Inseto/farmacologia , Proteínas de Insetos/isolamento & purificação , Proteínas de Insetos/farmacologia , Dados de Sequência Molecular , Peso Molecular , Proteínas do Tecido Nervoso/isolamento & purificação , Proteínas do Tecido Nervoso/farmacologia , Ovário/efeitos dos fármacos , Ovário/crescimento & desenvolvimentoRESUMO
Naturally produced and synthetically prepared reproductive hormones are frequently employed as pharmaceuticals in canine reproduction. Specific indications for the use of these preparations are few; too often hormonal therapies are used incorrectly and at times deleteriously. Appropriate uses of reproductive hormones are based on known physiological mechanisms in order to improve reproductive efficiency or to treat specific disorders.
Assuntos
Cães/fisiologia , Hormônios Esteroides Gonadais/farmacologia , Hormônio Liberador de Gonadotropina/farmacologia , Gonadotropinas/farmacologia , Reprodução/efeitos dos fármacos , Animais , Feminino , Hormônios Esteroides Gonadais/síntese química , Hormônio Liberador de Gonadotropina/análogos & derivados , Hormônio Liberador de Gonadotropina/síntese química , Gonadotropinas/síntese química , MasculinoRESUMO
Beside the gonadotrophines, that are used for therapeutical purposes since a rather long time, LHRH appeared as well as similar substances, whose actual clinical uses are mentioned.
