Klein, "Similar myogenic functions for myogenin and MRF4
but not MyoD in differentiated murine embryonic stem cells," Genesis, vol.
, Myf-5, and myogenin mRNAs in the adaptive responses of mature rat muscle," American Journal of Physiology--Cell Physiology, vol.
Mrf4, which is coexpressed with Myf5 at the onset of myogenesis, also acts as an early myogenic determination factor .
The transcript for MYOG was downregulated as shown in Figure 1(d) with unknown mechanisms; however, other myogenic factors, notably transcripts of MYOD1 or MRF4, were upregulated under conditions where MYOG is mutated in human myogenic cells (Figures 3(e)-3(g)).
Effect of mechanical stretching on expressions of muscle specific transcription factors MyoD, Myf5, Myogenin and MRF4
in proliferated myoblasts.
Four myogenic regulatory factors (MRFs), products of myogenic factor 5 (MYF5), myogenic differentiation (MYOD), myogenin (MYOG), and myogenic regulatory factor 4 (MRF4
) genes, are sequentially expressed during myogenesis where MYOD is required for inducing differentiation and formation of muscle fibers (Rehfeldt et al., 2011).
Collectively, MyoD, Myf5, MyoG, and Mrf4 are specifically expressed in skeletal muscle linage and are therefore referred to as myogenic regulatory factors (MRFs) (Weintraub et al., 1991).
To verify this hypothesis, we investigated the genetic polymorphisms of the MyoD, Myf5, MyoG, and Mrf4 genes in chickens and analyzed their association with muscle fibers traits.
MRFs such as myogenin, MRF4
, MyoD and Myf5 are expressed in anatomical- and time-dependent manners (Buckingham et al., 2003).
Transcription factors C/EBPa and PPARy (Figure 5) identified quantitatively by real time PCR when porcine satellite cells were transdifferentiated in the presence of ciglitizone and when expressed in G8 myoblasts, can suppress the muscle-specific transcription factors (Myf5, MyoD, myogenin and MRF4) (Hu et al., 1995).
Several proteins such as myogenic regulatory factors (MRFs), a group of skeletal-muscle specific basic helix-loop-helix (bHLH) transcription factors including of MyoD, Myf5, myogenin, and MRF4 have been documented and linked to myogenic differentiation.
Muscle fiber formation takes place during embryonic development and is regulated by the MyoD gene family, which consists of four genes, MyoD1 (MYF3), myogenin (MYOG or MYF4), MYF5 and MYF6 (MRF4