Control of the migratory pathway of facial branchiomotor neurones.
Facial branchiomotor (fbm) neurones undergo a complex migration in the segmented mouse hindbrain. They are born in the basal plate of rhombomere (r) 4, migrate caudally through r5, and then dorsally and radially in r6. To study how migrating cells adapt to their changing environment and control their pathway, we have analysed this stereotyped migration in wild-type and mutant backgrounds. We show that during their migration, fbm neurones regulate the expression of genes encoding the cell membrane proteins TAG-1, Ret and cadherin 8. Specific combinations of these markers are associated with each migratory phase in r4, r5 and r6. In Krox20 and kreisler mutant mouse embryos, both of which lack r5, fbm neurones migrate dorsally into the anteriorly positioned r6 and adopt an r6-specific expression pattern. In embryos deficient for Ebf1, a gene normally expressed in fbm neurones, part of the fbm neurones migrate dorsally within r5. Accordingly, fbm neurones prematurely express a combination of markers characteristic of an r6 location. These data suggest that fbm neurones adapt to their changing environment by switching on and off specific genes, and that Ebf1 is involved in the control of these responses. In addition, they establish a close correlation between the expression pattern of fbm neurones and their migratory behaviour, suggesting that modifications in gene expression participate in the selection of the local migratory pathway.
Garel
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S
Unité 368 de l'Institut National de la Santé et de la Recherche Médicale, Ecole Normale Supérieure, 75230 Paris Cedex 05, France.
Garcia-Dominguez
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M
Charnay
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P
D000818:Animals; D030161:Avian Proteins; D015820:Cadherins / Q000235:genetics / Q000502:physiology; D015816:Cell Adhesion Molecules, Neuronal; D002465:Cell Movement; D058969:Contactin 2; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology; D029721:Drosophila Proteins; D051767:Early Growth Response Protein 2; D005154:Facial Nerve / Q000166:cytology / Q000196:embryology*; D018507:Gene Expression Regulation, Developmental; D017403:In Situ Hybridization; D007763:Lac Operon; D051258:MafB Transcription Factor; D008562:Membrane Glycoproteins / Q000235:genetics / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D018345:Mice, Knockout; D008822:Mice, Transgenic; D009046:Motor Neurons / Q000166:cytology*; D009434:Neural Pathways / Q000166:cytology / Q000196:embryology; D015513:Oncogene Proteins; D011518:Proto-Oncogene Proteins; D051096:Proto-Oncogene Proteins c-ret; D020794:Receptor Protein-Tyrosine Kinases; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology
D030161:Avian Proteins; C548674:CNTN2 protein, human; D015820:Cadherins; C504541:Cdh8 protein, mouse; D015816:Cell Adhesion Molecules, Neuronal; C548675:Cntn2 protein, mouse; D058969:Contactin 2; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D051767:Early Growth Response Protein 2; C497327:Egr2 protein, mouse; C490407:MAFB protein, human; D051258:MafB Transcription Factor; C490406:Mafb protein, mouse; D008562:Membrane Glycoproteins; D015513:Oncogene Proteins; D011518:Proto-Oncogene Proteins; D014157:Transcription Factors; D051096:Proto-Oncogene Proteins c-ret; D020794:Receptor Protein-Tyrosine Kinases; C416649:Ret protein, Drosophila; C494999:Ret protein, mouse