Snail genes at the crossroads of symmetric and asymmetric processes in the developing mesoderm.
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.
Morales
Aixa V
AV
Instituto Cajal, CSIC, Doctor Arce 37, 28002 Madrid, Spain. aixamorales@cajal.csic.es
Acloque
Hervé
H
Ocaña
Oscar H
OH
de Frutos
Cristina A
CA
Gold
Veronica
V
Nieto
M Angela
MA
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
D012333:RNA, Messenger; C000604429:Snai1 protein, mouse; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors; D014212:Tretinoin