title: Sequential expression and redundancy of Pitx2 and Pitx3 genes during muscle development.
abstract: The myogenic program is controlled by different groups of transcription factors acting during muscle development, including bHLH muscle regulatory factors (MRFs), the paired factors Pax3 and Pax7 and the homeobox factors Six1 and Six4. This program is critically dependent on MRFs that target downstream muscle-specific genes. We now report the expression of Pitx2 and Pitx3 transcription factors throughout muscle development. Pitx2 is first expressed in muscle progenitor cells of the dermomyotome and myotome. The onset of myoblast differentiation is concomitant with expression of Pitx3; its expression is maintained in all skeletal muscles while Pitx2 expression decreases thereafter. We have generated Pitx3 mutant mice and this deficiency does not significantly perturb muscle development but it is completely compensated by the maintenance of Pitx2 expression in all skeletal muscles. These experiments suggest that Pitx genes are important for myogenesis and that Pitx2 and Pitx3 may have partly redundant roles.
authors.affiliation: Laboratoire de génétique moléculaire, Institut de Recherches Cliniques de Montréal (IRCM), 110, avenue des Pins Ouest, Montréal, QC, Canada H2W 1R7.
authors.forename: Aurore
authors.initials: A
authors.lastname: L'Honoré
authors.forename: Vincent
authors.initials: V
authors.lastname: Coulon
authors.forename: Alexandre
authors.initials: A
authors.lastname: Marcil
authors.forename: Mélanie
authors.initials: M
authors.lastname: Lebel
authors.forename: Julien
authors.initials: J
authors.lastname: Lafrance-Vanasse
authors.forename: Philip
authors.initials: P
authors.lastname: Gage
authors.forename: Sally
authors.initials: S
authors.lastname: Camper
authors.forename: Jacques
authors.initials: J
authors.lastname: Drouin
mesh_terms: D000818:Animals; D001483:Base Sequence; D002454:Cell Differentiation / Q000235:genetics; D017931:DNA Primers / Q000235:genetics; D005260:Female; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000235:genetics*; D017403:In Situ Hybridization; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008954:Models, Biological; D024510:Muscle Development / Q000235:genetics*; D018482:Muscle, Skeletal / Q000196:embryology* / Q000378:metabolism*; D032448:Myoblasts, Skeletal / Q000166:cytology / Q000378:metabolism; D011247:Pregnancy; D014157:Transcription Factors / Q000172:deficiency / Q000235:genetics*; D000097577:Homeobox Protein PITX2
chemical_list: D017931:DNA Primers; D018398:Homeodomain Proteins; D014157:Transcription Factors; D000097577:Homeobox Protein PITX2; C433629:homeobox protein PITX3