title: Retinoic acid affects left-right patterning.
abstract: Our understanding of the means by which the left-right axis is patterned is not fully understood, although a number of key intermediaries have been recently described. We report here that retinoic acid (RA) excess affects heart situs concomitant with alterations in the expression of genes implicated in the establishment of the left-right axis. Specifically, RA exposure during a specific developmental window evoked bilateral expression of lefty-1, lefty-2, nodal, and pitx-2 in the lateral plate mesoderm. Time course experiments, together with analysis of midline markers, suggest that nascent mesoderm constitutes a predominant RA target involved in this process. These events are likely to underlie the perturbations of heart looping provoked by excess RA and suggest a means by which retinoids influence the early steps in establishment of the left-right embryonic axis.
authors.affiliation: Department of Molecular Biology, Université de Montréal, Montréal, Québec, Canada.
authors.forename: S
authors.initials: S
authors.lastname: Wasiak
authors.forename: D
authors.initials: D
authors.lastname: Lohnes
mesh_terms: D000818:Animals; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D006321:Heart / Q000196:embryology*; D018398:Homeodomain Proteins / Q000235:genetics; D055458:Left-Right Determination Factors; D008297:Male; D051379:Mice; D055457:Nodal Protein; D009687:Nuclear Proteins; D009924:Organ Culture Techniques; D051761:Paired Box Transcription Factors; D011247:Pregnancy; D014157:Transcription Factors / Q000235:genetics; D016212:Transforming Growth Factor beta / Q000235:genetics; D014212:Tretinoin / Q000494:pharmacology*; D000097577:Homeobox Protein PITX2
chemical_list: D018398:Homeodomain Proteins; D055458:Left-Right Determination Factors; D055457:Nodal Protein; D009687:Nuclear Proteins; D051761:Paired Box Transcription Factors; D014157:Transcription Factors; D016212:Transforming Growth Factor beta; D014212:Tretinoin; D000097577:Homeobox Protein PITX2; C526008:Nodal protein, mouse; C101485:homeobox protein PITX1; C433629:homeobox protein PITX3