Localization of mRNAs coding for CMD1, myogenin and the alpha-subunit of the acetylcholine receptor during skeletal muscle development in the chicken.
Myogenin and CMD1, the chicken homologue of MyoD, transactivate the promoter of the alpha-subunit of the acetylcholine receptor (AChR) in chicken fibroblasts. The expression of these three genes was followed by in situ hybridization. In two-day-old embryos the CMD1 gene is expressed shortly before the AChR alpha-subunit and the myogenin genes. At day 19 extrajunctional AChR mRNA clusters have disappeared and myogenin mRNAs are no longer detected in PLD muscle. Moreover, both myogenin and CMD1 mRNA levels increase after muscle denervation in chicks. These data are compatible with a role for myogenic factors in the induction and maintenance of extra-junctional expression of the AChR genes during early muscle development. Using digoxygenin labelled RNA probes, we also show that the mRNAs for the AChR alpha-subunit display a punctated, probably perinuclear distribution, whereas mRNAs for myogenic genes accumulate in the sarcoplasm around subsets of nuclei in the muscle fiber.
Piette
J
J
UA CNRS D1284 Neurobiologie Moléculaire, Institut Pasteur, Paris, France.
Huchet
M
M
Duclert
A
A
Fujisawa-Sehara
A
A
Changeux
J P
JP
D000818:Animals; D002478:Cells, Cultured; D002642:Chick Embryo; D002645:Chickens / Q000235:genetics* / Q000254:growth & development; D003714:Denervation; D005347:Fibroblasts / Q000378:metabolism; D005786:Gene Expression Regulation; D024510:Muscle Development; D009124:Muscle Proteins / Q000096:biosynthesis / Q000235:genetics*; D009132:Muscles / Q000196:embryology / Q000378:metabolism*; D017570:MyoD Protein; D018008:Myogenin; D009693:Nucleic Acid Hybridization; D009928:Organ Specificity; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000032:analysis*; D011950:Receptors, Cholinergic / Q000096:biosynthesis / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D013045:Species Specificity; D015533:Transcriptional Activation
D009124:Muscle Proteins; D017570:MyoD Protein; D018008:Myogenin; D012333:RNA, Messenger; D011950:Receptors, Cholinergic; D011993:Recombinant Fusion Proteins