RESUMEN

MicroRNAs (miRNAs) have gradually been recognized as regulators of embryonic development; however, relatively few miRNAs have been identified that regulate cardiac development. A series of recent papers have established an essential role for the miRNA-17-92 (miR-17-92) cluster of miRNAs in the development of the heart. Previous research has shown that the Friend of Gata-2 (FOG-2) is critical for cardiac development. To investigate the possibility that the miR-17-92 cluster regulates FOG-2 expression and inhibits proliferation in mouse embryonic cardiomyocytes we initially used bioinformatics to analyze 3’ untranslated regions (3’UTR) of FOG-2 to predict the potential of miR-17-92 to target it. We used luciferase assays to demonstrate that miR-17-5p and miR-20a of miR-17-92 interact with the predicted target sites in the 3’UTR of FOG-2. Furthermore, RT-PCR and Western blot were used to demonstrate the post-transcriptional regulation of FOG-2 by miR-17-92 in embryonic cardiomyocytes from E12.5-day pregnant C57BL/6J mice. Finally, EdU cell assays together with the FOG-2 rescue strategy were employed to evaluate the effect of proliferation on embryonic cardiomyocytes. We first found that the miR-17-5p and miR-20a of miR-17-92 directly target the 3’UTR of FOG-2 and post-transcriptionally repress the expression of FOG-2. Moreover, our findings demonstrated that over-expression of miR-17-92 may inhibit cell proliferation via post-transcriptional repression of FOG-2 in embryonic cardiomyocytes. These results indicate that the miR-17-92 cluster regulates the expression of FOG-2 protein and suggest that the miR-17-92 cluster might play an important role in heart development.

Asunto(s)

Animales , Femenino , Ratones , Embarazo , /genética , Proteínas de Unión al ADN/genética , MicroARNs/genética , Miocitos Cardíacos/citología , Factores de Transcripción/genética , Técnicas de Cultivo de Célula , Proliferación Celular , Biología Computacional , Proteínas de Unión al ADN/metabolismo , Luciferasas/farmacología , Ratones Transgénicos , MicroARNs/metabolismo , Plásmidos/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Transfección , Factores de Transcripción/metabolismo

RESUMEN

MicroRNAs (miRNAs) have gradually been recognized as regulators of embryonic development; however, relatively few miRNAs have been identified that regulate cardiac development. A series of recent papers have established an essential role for the miRNA-17-92 (miR-17-92) cluster of miRNAs in the development of the heart. Previous research has shown that the Friend of Gata-2 (FOG-2) is critical for cardiac development. To investigate the possibility that the miR-17-92 cluster regulates FOG-2 expression and inhibits proliferation in mouse embryonic cardiomyocytes we initially used bioinformatics to analyze 3' untranslated regions (3'UTR) of FOG-2 to predict the potential of miR-17-92 to target it. We used luciferase assays to demonstrate that miR-17-5p and miR-20a of miR-17-92 interact with the predicted target sites in the 3'UTR of FOG-2. Furthermore, RT-PCR and Western blot were used to demonstrate the post-transcriptional regulation of FOG-2 by miR-17-92 in embryonic cardiomyocytes from E12.5-day pregnant C57BL/6J mice. Finally, EdU cell assays together with the FOG-2 rescue strategy were employed to evaluate the effect of proliferation on embryonic cardiomyocytes. We first found that the miR-17-5p and miR-20a of miR-17-92 directly target the 3'UTR of FOG-2 and post-transcriptionally repress the expression of FOG-2. Moreover, our findings demonstrated that over-expression of miR-17-92 may inhibit cell proliferation via post-transcriptional repression of FOG-2 in embryonic cardiomyocytes. These results indicate that the miR-17-92 cluster regulates the expression of FOG-2 protein and suggest that the miR-17-92 cluster might play an important role in heart development.

Asunto(s)

Regiones no Traducidas 3'/genética , Proteínas de Unión al ADN/genética , MicroARNs/genética , Miocitos Cardíacos/citología , Factores de Transcripción/genética , Animales , Técnicas de Cultivo de Célula , Proliferación Celular , Biología Computacional , Proteínas de Unión al ADN/metabolismo , Femenino , Luciferasas/farmacología , Ratones , Ratones Transgénicos , MicroARNs/metabolismo , Plásmidos/genética , Embarazo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Factores de Transcripción/metabolismo , Transfección

RESUMEN

The quantitative trait loci (QTLs) associated with cocoon traits in silkworms were mapped in 44 individuals of a backcross of Dazao females with hybrid F(1) males; the hybrid males were from females of inbred C(1)00 strain, which have white cocoons and superior cocoon traits, crossed with males of inbred strain Dazao, which have green cocoons and inferior cocoon traits. Nineteen putative major QTLs of silkworm cocoon traits, five QTLs of whole cocoon weight, four QTLs of cocoon shell weight, six QTLs of pupa weight, and four QTLs of cocoon shell rate were scattered across nine linkage groups. The variances explained by QTLs for whole cocoon weight, cocoon shell weight, pupa weight, and cocoon shell rate were 51.0, 73.69, 51.80, and 59.52%, respectively. The numbers of major QTLs with contributions above 10% for these traits were two, three, two, and four, respectively.

Asunto(s)

Bombyx/genética , Cruzamiento , Sitios de Carácter Cuantitativo , Animales , Cruzamientos Genéticos , Femenino , Masculino , Mapeo Físico de Cromosoma , Pigmentación/genética

RESUMEN

Bombyx mori and Bombyx mandarina are morphologically and physiologically similar. In this study, we compared the nucleotide variations in the complete mitochondrial (mt) genomes between the domesticated silkmoth, B. mori, and its wild ancestors, Chinese B. mandarina (ChBm) and Japanese B. mandarina (JaBm). The sequence divergence and transition mutation ratio between B. mori and ChBm are significantly smaller than those observed between B. mori and JaBm. The preference of transition by DNA strands between B. mori and ChBm is consistent with that between B. mori and JaBm, however, the regional variation in nucleotide substitution rate shows a different feature. These results suggest that the ChBm mt genome is not undergoing the same evolutionary process as JaBm, providing evidence for selection on mtDNA. Moreover, investigation of the nucleotide sequence divergence in the A+T-rich region of Bombyx mt genomes also provides evidence for the assumption that the A+T-rich region might not be the fastest evolving region of the mtDNA of insects.

RESUMEN

Bombyx mori and Bombyx mandarina are morphologically and physiologically similar. In this study, we compared the nucleotide variations in the complete mitochondrial (mt) genomes between the domesticated silkmoth, B. mori, and its wild ancestors, Chinese B. mandarina (ChBm) and Japanese B. mandarina (JaBm). The sequence divergence and transition mutation ratio between B. mori and ChBm are significantly smaller than those observed between B. mori and JaBm. The preference of transition by DNA strands between B. mori and ChBm is consistent with that between B. mori and JaBm, however, the regional variation in nucleotide substitution rate shows a different feature. These results suggest that the ChBm mt genome is not undergoing the same evolutionary process as JaBm, providing evidence for selection on mtDNA. Moreover, investigation of the nucleotide sequence divergence in the A+T-rich region of Bombyx mt genomes also provides evidence for the assumption that the A+T-rich region might not be the fastest evolving region of the mtDNA of insects.