title: Snail genes at the crossroads of symmetric and asymmetric processes in the developing mesoderm.
abstract: Retinoic acid (RA) signalling ensures that vertebrate mesoderm segmentation is bilaterally synchronized, and corrects transient interferences from asymmetric left-right (L-R) signals involved in organ lateralization. Snail genes participate in both these processes and, although they are expressed symmetrically in the presomitic mesoderm (PSM), Snail1 transcripts are asymmetrically distributed in the L-R lateral mesoderm. We show that the alteration of the symmetric Snail expression in the PSM induces asynchronous somite formation. Furthermore, in the absence of RA signalling, normal asymmetric Snail1 expression in the lateral mesoderm is extended to the PSM, desynchronizing somitogenesis. Thus, Snail1 is the first cue corrected by RA in the PSM to ensure synchronized bilateral segmentation.
authors.affiliation: Instituto Cajal, CSIC, Doctor Arce 37, 28002 Madrid, Spain. aixamorales@cajal.csic.es
authors.forename: Aixa V
authors.initials: AV
authors.lastname: Morales
authors.forename: Hervé
authors.initials: H
authors.lastname: Acloque
authors.forename: Oscar H
authors.initials: OH
authors.lastname: Ocaña
authors.forename: Cristina A
authors.initials: CA
authors.lastname: de Frutos
authors.forename: Veronica
authors.initials: V
authors.lastname: Gold
authors.forename: M Angela
authors.initials: MA
authors.lastname: Nieto
mesh_terms: D000818:Animals; D019521:Body Patterning / Q000187:drug effects / Q000235:genetics*; D002642:Chick Embryo; D047108:Embryonic Development / Q000235:genetics*; D015870:Gene Expression / Q000187:drug effects; D008648:Mesoderm / Q000737:chemistry / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D034622:RNA Interference; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D000071250:Snail Family Transcription Factors; D019170:Somites / Q000737:chemistry / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics*; D014212:Tretinoin / Q000494:pharmacology
chemical_list: D012333:RNA, Messenger; C000604429:Snai1 protein, mouse; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors; D014212:Tretinoin