Myogenic factor 6 (also known as Mrf4 or herculin) is a

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...

that in humans is encoded by the MYF6

gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...

. This gene is also known in the biomedical literature as MRF4 and herculin. MYF6 is a

myogenic regulatory factor Myogenic regulatory factors (MRF) are basic helix-loop-helix (bHLH) transcription factors that regulate myogenesis: MyoD, Myf5, myogenin, and MRF4. These proteins contain a conserved basic DNA binding domain that binds the E box DNA motif. Th ...

(MRF) involved in the process known as

myogenesis Myogenesis is the formation of skeletal muscle, skeletal muscular tissue, particularly during embryonic development. Skeletal muscle#Skeletal muscle cells, Muscle fibers generally form through the fusion of precursor cell, precursor myoblasts in ...

Function

MYF6/Mrf4 is a member of the myogenic factor (MRF) family of transcription factors that regulate skeletal muscle

and muscle regeneration. Myogenic factors are

basic helix-loop-helix Basic or BASIC may refer to: Science and technology * BASIC, a computer programming language * Basic (chemistry), having the properties of a base * Basic access authentication, in HTTP Entertainment * ''Basic'' (film), a 2003 film * Basic, one ...

(bHLH)

transcription factor In molecular biology, a transcription factor (TF) (or sequence-specific DNA-binding factor) is a protein that controls the rate of transcription (genetics), transcription of genetics, genetic information from DNA to messenger RNA, by binding t ...

s. MYF6 is a gene that encodes a protein involved in the regulation of

. The precise role(s) of Myf6/Mrf4 in myogenesis are unclear, although in mice it is able to initiate myogenesis in the absence of Myf5 and MyoD, two other MRFs. The portion of the protein integral to myogenesis regulation requires the basic helix-loop-helix (bHLH) domain that is conserved among all of the genes in the MRF family. MYF6 is expressed exclusively in skeletal muscle, and it is expressed at a higher levels in adult skeletal muscle than all of the other MRF family genes. In mouse, Myf6/Mrf4 differs somewhat from the other MRF genes due to its two-phase expression. Initially, Myf6 is transiently expressed along with Myf-5 in the

somite The somites (outdated term: primitive segments) are a set of bilaterally paired blocks of paraxial mesoderm that form in the embryogenesis, embryonic stage of somitogenesis, along the head-to-tail axis in segmentation (biology), segmented animals. ...

s during the early stages of myogenesis. However, it is more noticeably expressed postnatally. This suggests that it serves an important role in the maintenance and repair of adult skeletal muscle. The MYF6 gene is physically linked to the MYF5 gene on chromosome 12, and similar linkage is observed in all vertebrates. Mutations in the mouse Myf6 gene typically exhibit reduced levels of Myf5. Despite reductions in muscle mass of the back and defective rib formation, Myf6 mutants still exhibit fairly normal skeletal muscle. This demonstrates that Myf6 is not essential for the formation of most myofibers, at least in the strains of mice tested. In zebrafish, Myf6/Mrf4 is expressed in all terminally differentiated muscle examined, but expression has not been reported in muscle precursor cells.

Clinical significance

Mutations in the ''MYF6'' gene are associated with autosomal dominant centronuclear myopathy (ADCNM) and

Becker's muscular dystrophy Becker muscular dystrophy (BMD) is an X-linked recessive inherited disorder characterized by slowly progressing muscle weakness of the legs and pelvis. It is a type of dystrophinopathy. The cause is mutations and deletions in any of the 79 exons ...

Function

Clinical significance

References

Further reading