title: MicroRNA regulation of the paired-box transcription factor Pax3 confers robustness to developmental timing of myogenesis.
abstract: Commitment of progenitors in the dermomyotome to myoblast fate is the first step in establishing the body musculature. Pax3 is a crucial transcription factor, important for skeletal muscle development and expressed in myogenic progenitors in the dermomyotome of developing somites and in migratory muscle progenitors that populate the limb buds. Down-regulation of Pax3 is essential to ignite the myogenic program, including up-regulation of myogenic regulators, Myf-5 and MyoD. MicroRNAs (miRNAs) confer robustness to developmental timing by posttranscriptional repression of genetic programs that are related to previous developmental stages or to alternative cell fates. Here we demonstrate that the muscle-specific miRNAs miR-1 and miR-206 directly target Pax3. Antagomir-mediated inhibition of miR-1/miR-206 led to delayed myogenic differentiation in developing somites, as shown by transient loss of myogenin expression. This correlated with increased Pax3 and was phenocopied using Pax3-specific target protectors. Loss of myogenin after antagomir injection was rescued by Pax3 knockdown using a splice morpholino, suggesting that miR-1/miR-206 control somite myogenesis primarily through interactions with Pax3. Our studies reveal an important role for miR-1/miR-206 in providing precision to the timing of somite myogenesis. We propose that posttranscriptional control of Pax3 downstream of miR-1/miR-206 is required to stabilize myoblast commitment and subsequent differentiation. Given that mutually exclusive expression of miRNAs and their targets is a prevailing theme in development, our findings suggest that miRNA may provide a general mechanism for the unequivocal commitment underlying stem cell differentiation.
authors: Department of Cell and Developmental Biology, University of East Anglia, Norwich NR4 7TJ, United Kingdom.
authors: Katarzyna
authors: K
authors: Goljanek-Whysall
authors: Dylan
authors: D
authors: Sweetman
authors: Muhammad
authors: M
authors: Abu-Elmagd
authors: Elik
authors: E
authors: Chapnik
authors: Tamas
authors: T
authors: Dalmay
authors: Eran
authors: E
authors: Hornstein
authors: Andrea
authors: A
authors: Münsterberg
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002454:Cell Differentiation / Q000235:genetics / Q000502:physiology*; D002478:Cells, Cultured; D053487:DEAD-box RNA Helicases / Q000235:genetics / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental / Q000235:genetics / Q000502:physiology*; D055879:Gene Knock-In Techniques; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D051379:Mice; D035683:MicroRNAs / Q000378:metabolism*; D024510:Muscle Development / Q000235:genetics / Q000502:physiology*; D018008:Myogenin / Q000378:metabolism; D009841:Oligonucleotides / Q000008:administration & dosage / Q000235:genetics; D000072041:PAX3 Transcription Factor; D051761:Paired Box Transcription Factors / Q000378:metabolism*; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D043244:Ribonuclease III / Q000235:genetics / Q000378:metabolism
chemical_list: D035683:MicroRNAs; C517731:Mirn1 microRNA, mouse; C540669:Mirn206 microRNA, mouse; C503801:Myog protein, mouse; D018008:Myogenin; D009841:Oligonucleotides; D000072041:PAX3 Transcription Factor; D051761:Paired Box Transcription Factors; C068686:Pax3 protein, mouse; C509781:Dicer1 protein, mouse; D043244:Ribonuclease III; D053487:DEAD-box RNA Helicases