Editing Muscle cell (section)

==Development{{anchor|Myonuclei}}==
{{Main|Myogenesis}}

A [[myoblast]] is an embryonic [[precursor cell]] that [[Cellular differentiation|differentiates]] to give rise to the different muscle cell types.<ref>page 395, Biology, Fifth Edition, Campbell, 1999</ref> Differentiation is regulated by [[myogenic regulatory factors]], including [[MyoD]], [[Myf5]], [[myogenin]], and [[MRF4]].<ref>{{cite journal |vauthors=Perry R, Rudnick M |title=Molecular mechanisms regulating myogenic determination and differentiation |journal=Front Biosci |volume=5 |pages=D750–67 |year= 2000|pmid=10966875 |doi=10.2741/Perry|doi-access=free }}</ref> [[GATA4]] and [[GATA6]] also play a role in myocyte differentiation.<ref name="pmid18400219">{{cite journal |vauthors=Zhao R, Watt AJ, Battle MA, Li J, Bandow BJ, Duncan SA |title=Loss of both GATA4 and GATA6 blocks cardiac myocyte differentiation and results in acardia in mice |journal=Dev. Biol. |volume=317 |issue=2 |pages=614–9 |date=May 2008 |pmid=18400219 |pmc=2423416 |doi=10.1016/j.ydbio.2008.03.013 }}</ref>

[[Skeletal muscle#Skeletal muscle cells|Skeletal muscle fibers]] are made when myoblasts fuse together; muscle fibers therefore are cells with [[Multinucleate|multiple nuclei]], known as [[myonuclei]], with each [[cell nucleus]] originating from a single myoblast. The fusion of myoblasts is specific to skeletal muscle, and not [[cardiac muscle]] or [[smooth muscle]].

Myoblasts in skeletal muscle that do not form muscle fibers [[Dedifferentiation|dedifferentiate]] back into [[myosatellite cell]]s. These satellite cells remain adjacent to a skeletal muscle fiber, situated between the sarcolemma and the basement membrane<ref>{{cite journal|last1=Zammit|first1=PS|last2=Partridge|first2=TA|last3=Yablonka-Reuveni|first3=Z|title=The skeletal muscle satellite cell: the stem cell that came in from the cold.|journal=Journal of Histochemistry and Cytochemistry|date=November 2006|volume=54|issue=11|pages=1177–91|pmid=16899758|doi=10.1369/jhc.6r6995.2006|doi-access=free}}</ref> of the [[endomysium]] (the connective tissue investment that divides the muscle fascicles into individual fibers). To re-activate myogenesis, the satellite cells must be stimulated to differentiate into new fibers.

Myoblasts and their derivatives, including satellite cells, can now be generated in vitro through [[directed differentiation]] of [[Induced pluripotent stem cells|pluripotent stem cells]].<ref name="pmid26237517">{{cite journal |vauthors = Chal J, Oginuma M, Al Tanoury Z, Gobert B, Sumara O, Hick A, Bousson F, Zidouni Y, Mursch C, Moncuquet P, Tassy O, Vincent S, Miyazaki A, Bera A, Garnier JM, Guevara G, Heston M, Kennedy L, Hayashi S, Drayton B, Cherrier T, Gayraud-Morel B, Gussoni E, Relaix F, Tajbakhsh S, Pourquié O|title = Differentiation of pluripotent stem cells to muscle fiber to model Duchenne muscular dystrophy |journal = [[Nat. Biotechnol.|Nature Biotechnology]]|date = August 2015|pmid = 26237517|doi = 10.1038/nbt.3297 |volume=33 |issue = 9 |pages=962–9|s2cid = 21241434 |url = http://www.hal.inserm.fr/inserm-01484878}} {{Closed access}}</ref>

[[Kindlin-2]] plays a role in developmental elongation during myogenesis.<ref name="pmid18611274">{{cite journal |vauthors=Dowling JJ, Vreede AP, Kim S, Golden J, Feldman EL |title=Kindlin-2 is required for myocyte elongation and is essential for myogenesis |journal=BMC Cell Biol. |volume=9 |pages=36 |year=2008 |pmid=18611274 |pmc=2478659 |doi=10.1186/1471-2121-9-36 |doi-access=free }}</ref>