Differential expression patterns of myogenic regulatory factors in the postnatal longissimus dorsi muscle of Jeju Native Pig and Berkshire breeds along with their co-expression with Pax7

BACKGROUND: Myogenic regulatory factors (MRFs) such as MyoD, Myf6 and Myf5 play a vital role in the growth and development of muscles. Jeju Native Pig (JNP) is the top ranker in Korea amongst the indigenous livestock reared for meat purpose. Few studies covering transcript abundance of the MRFs and related to their co-expression with Pax7 in JNP have been conducted. Despite having better quality pork, JNP does not have a comparative growth rate with respect to western breeds. Therefore, the present study was designed with the objective to study the relative transcript levels of MRFs in the postnatal myogenesis of longissimus dorsi muscles in JNP and Berkshire breeds. RESULTS: Relative transcript levels were analyzed by qRT-PCR and blot expression analysis through Western blotting. Immunocytochemistry was performed to analyze their expressions at cellular levels. ToppCluster aided in the analysis of gene ontology of biological processes. The quantitative transcript levels of MyoD and Pax7 were significantly (P < 0.05) higher in Berkshire than in JNP. Myotube formation was observed under the co-expression of MyoD and Pax7. ToppCluster helped in the understanding of the linking of biological processes of the MRFs with the different signaling pathways. MyBPH had significantly (P < 0.05) high transcript levels during the chosen age groups in JNP than Berkshire. CONCLUSIONS: The current study can be helpful in understanding the genetic basis for myogenesis in postnatal stage. Moreover, it can act as stepping stone for the identification of marker genes related to body growth and meat quality in JNP.

Regiones del cromosoma 5 asociadas a características de crecimiento en ganado criollo romosinuano / Chromosomal 5 regions associated with growth traits in the romosinuan o creole cattle

El crecimiento es una de las características de naturaleza cuantitativa que influye en la calidad de la canal. En el presente estudio se identificaron las regiones cromosomales responsables para la variación del crecimiento en el cromosoma 5 en una población de ganado criollo romosinuano. Se evaluaron en 72 progenies las características de peso alnacimiento, peso al destete, peso a los 12 meses y a los 16 meses, área de ojo del lomo alos 12 y 16 meses, espesor de grasa dorsal a los 12 y 16 meses, espesor de grasa del anca a los 12 y 16 meses, ganancia diaria predestete y posdestete, al igual que los genotipos de tres polimorfismos de nucleótido simple de los genes MYF5, PDE1B e IGF1 y decuatro microsatélites BM6026, CSSM34, RM500, ETH10, distribuidos a lo largo del cromosoma. Se realizó un análisis de regresión linear el cual mostró el efecto de seis loci de rasgos cuantitativos (QTL) asociados a características de crecimiento. Cinco QTL fueron significativos (p≤0,05) para las características de peso al nacimiento, peso a los16 meses, área del ojo de lomo a los 12 y 16 meses y ganancia diaria posdestete y un QTL se encontró con una significancia de p≤0,01 para la característica ganancia diaria predestete. Los resultados demostraron que los genes MYF5, PDE1B, IGF1 pueden ser genes candidatos posicionales que inciden en la variación del crecimiento para la calidad de la canal en el ganado romosinuano.

Growth is a quantitative trait that influences the carcass quality. In the present study, bovine chromosomal 5 regions responsible for growth variations have been identified in a Romosinuano creole cattle population. The traits birth weight, weaning weight,12 months weight, 16 months weight, the rib eye area at 12 and 16 months, back fatthickness at 12 and 16 months, rump fat thickness at 12 and 16 months, preweaning and postweaning daily gain were evaluated in 72 progenies, as well as the genotypes of 3 SNPs from the MYF5, PDE1B, IGF1 genes and 4 microsatellites (BM6026,CSSM34, RM500, ETH10) distributed along the chromosome. A linear regression analysis showed the six QTL effect associated with growth traits. Five QTL were significant at p≤0.05 for the triait birth weight, weight at 16 months, rib eye area at 12 and 16 months, and preweaning daily gain interval between 45 and 105 cM and aQTL showed a level significance of p ≤ 0.01 for the postweaning daily gain. It was demostrated according to the position of the QTLs identified in the present study, that the MYF5, PDE1B and IGF1 genes might be positional candidate genes affecting the growth variation for carcass quality in Romosinuano cattle.