Developmental molecular switches regulating breathing patterns in CNS.
The present paper presents some of the molecular switches that may operate at early embryonic stages to make development of the brainstem respiratory rhythm generator a robust and irreversible process. We concentrate on the role of transient Hox-related gene expression patterns in register with the regionalisation of the rhombencephalic neural tube along the antero-posterior axis. Using different recording and isolation procedures in chick embryos, we show that the hindbrain is subdivided at E1 into developmental units (rhombomeres) intrinsically able to produce rhythm generating neuronal circuits active at E5. At E6, intrinsic cues also allow a progressive maturation of episodic rhythm generators that persists after isolation of the hindbrain in vitro and requires odd/even rhombomeric interactions at E1. From these results and from respiratory pathologies observed in transgenic mice, we are beginning to understand that, despite diversity of breathing patterns and adaptations, there are links between developmental control genes and adult respiration.
Borday
Caroline
C
UPR 2216 Neurobiologie Génétique et Intégrative, Institut de Neurobiologie Alfred Fessard, C.N.R.S., 1, av. de la Terrasse, 91198, Gif-sur-Yvette, France. caroline.borday@iaf.cnrs-gif.fr
Abadie
Véronique
V
Chatonnet
Fabrice
F
Thoby-Brisson
Muriel
M
Champagnat
Jean
J
Fortin
Gilles
G
D000818:Animals; D002490:Central Nervous System / Q000033:anatomy & histology / Q000196:embryology* / Q000254:growth & development; D004594:Electrophysiology / Q000379:methods; D004622:Embryo, Mammalian; D004625:Embryo, Nonmammalian; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D005801:Genes, Homeobox; D005812:Genes, Switch / Q000235:genetics* / Q000502:physiology; D008954:Models, Biological; D012119:Respiration / Q000235:genetics*