Expression profile of MYF5 and MYF6 genes in skeletal muscles of young growing gilts of five breeds at different ages, based on the most stable reference genes

The expression profile was evaluated of MYF5 and MYF6 genes in skeletal muscles of young growing Polish Large White (PLW), Polish Landrace (PL), Pietrain (PIE), Duroc (DUR) and Pulawska (PUL) gilts at different ages. Normalization of MYF5 and MYF6 was performed on reliable porcine reference genes (PRGs), where expression stabilities of nine of them (ACTB, B2M, GAPDH, SDHA, HPRTI, RPL13A, YWHAZ, TBP, TOP2B) were evaluated by RT-qPCR method and NormFinder software. Results revealed HPRTI, TBP and TOP2B as highly stable and PRGs. The age-dependent and breed-specific skeletal muscle expression comparisons revealed highly significant (P<0.01) differences in MYF6 expression levels of all skeletal muscles among investigated breeds. MYF6 gene expression in PIE and DUR were higher compared to PLW, PL and PUL gilts. Contrarily, paired-wise comparison of MYF5 gene expression showed only significant difference between DUR and PUL for semimembranosus, and PL and PLW, DUR and PL, PIE and PL, DUR and PUL and PIE and PUL for gluteus medius muscle. There was no significant relationship identified between gilt ages and the level of expression of MYF5 and MYF6 genes. However, their highest expression was identified in longissimus dorsi followed by gluteus medius and semimembranosus muscles. It is concluded that normalization of gene expression has to be done on more than one PRG to reduce the errors in transcription level estimates. Moreover, significantly different breed-specific expression of porcine MYF5 and MYF6 allowed the authors to prioritize these genes as potential candidate genes for trait-associated study.