RESUMO
The genes insulin-like growth factor 2 (IGF2) and H19 express paternally and maternally, respectively, in humans, mice, sheep, and cattle. Additionally, IGF2 has been shown to be regulated by at least four promoters in a tissue- or development-specific manner. In the domestic pigs, the promoter- and tissue-specific imprinting pattern of IGF2 has not been well characterized, nor is the imprinting pattern of H19. In the present study, we identified two polymorphisms in each of IGF2 (exons 2 and 9) and H19 (exons 1 and 5) and determined the imprinting status of these two genes in 13 organs / tissues of week-old pigs. IGF2 P1 transcript is bi-allelically expressed (not imprinted) in all major organs studied, while the majority of IGF2 transcripts are expressed from promoters 2-4 and are imprinted. H19 is exclusively expressed from the maternal allele in all major organs, concurrent with observations in other species.
Assuntos
Impressão Genômica , Fator de Crescimento Insulin-Like II/genética , RNA não Traduzido/genética , Suínos/genética , Animais , Genoma , Masculino , Polimorfismo Genético , RNA Longo não Codificante , Sêmen/citologia , Sêmen/fisiologia , Pele/citologiaRESUMO
We report here the ontogenic changes in mRNA expression of chicken ghrelin (cGhrelin) and its receptor (cGHS-R1a) and the effects of fasting and refeeding on cGhrelin and cGHS-R1a mRNAs expression in 30-day-old broiler chickens. The level of cGhrelin mRNA in the proventriculus was low from embryo--day 15 (E15) to E19, but dramatically increased at post-hatching-day 2 (P2), then remained constant until P30 and followed by a significant decrease at P44 when there was a diet transition at P31 and thereafter. The decreased level was reversed at P58. Hypothalamic cGhrelin mRNA and proventriculus and hepatic cGHS-R1a mRNA were significantly increased at P30. The cGhrelin mRNA level in the proventriculus significantly increased in response to either 12-h or 36-h fasting but did not decrease after subsequent 12-h refeeding. The level of cGHS-R1a mRNA in the proventriculus was significantly upregulated in response to a 12-h fast but not to a 36-h fast and returned to the control level upon 12-h refeeding. Interestingly, it was apparent that the mRNA levels of both cGhrelin and cGHS-R1a in the liver were upregulated in response to fasting in a time-dependent manner and returned to the control level with subsequent refeeding. These results suggest that the expression pattern of ghrelin and its receptor mRNAs distinctly change in tissues depending on ontogenic stages and feeding states in poultry.
Assuntos
Galinhas/genética , Comportamento Alimentar , Hipotálamo/metabolismo , Fígado/metabolismo , Hormônios Peptídicos/genética , Proventrículo/metabolismo , Receptores Acoplados a Proteínas G/genética , Animais , Privação de Alimentos , Regulação da Expressão Gênica , Grelina , Ligantes , Masculino , Hormônios Peptídicos/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Receptores de GrelinaRESUMO
The domestic cattle (Bos taurus) has been a good animal model for embryo biotechnologies, such as in vitro fertilization and nuclear transfer. However, animals produced from these technologies often suffer from large-calf syndrome, suggesting fetal growth disregulation. The product of the insulin-like growth factor 2 (IGF2) gene is one of the most important fetal mitogens known to date. A detailed analysis of age-, tissue-, and allele-specific expression of IGF2 has not been performed in the bovine mainly because the majority of the bovine sequence has been unavailable. In the present study, we obtained virtually the entire sequence of the bovine IGF2 cDNA, identified expressed single-nucleotide polymorphisms (SNPs) in both exons 3 and 10, and determined the age-, tissue-, and promoter-specific expression of bovine IGF2 in fetal, calf, and adult tissues. We found that, similar to the human and mouse, bovine IGF2 is subjected to extensive transcriptional regulation through multiple promoters, alternative splicing and polyadenylation, as well as genetic imprinting. However, major differences were found in the regulation of the bovine IGF2 in nearly all aspects of age-, tissue-, promoter-, and allele-specific expression of IGF2, and the promoter-specific loss of imprinting from every other species studied, including cattle's close relatives, the sheep and the pig. The data presented here are of important reference value to cattle produced from embryo biotechnologies.