Neural tube patterning by Krox20 and emergence of a respiratory control
Respiratory Physiology & Neurobiology. 2005-11-01; 149(1-3): 63-72
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1. Respir Physiol Neurobiol. 2005 Nov 15;149(1-3):63-72.
Neural tube patterning by Krox20 and emergence of a respiratory control.
Borday C(1), Chatonnet F, Thoby-Brisson M, Champagnat J, Fortin G.
(1)UPR 2216 Neurobiologie Génétique et Integrative, Institut fédératif de
Neurobiologie Alfred Fessard, C.N.R.S., 1, Avenue de la Terrasse, 91198 Gif sur
Yvette Cedex, France.
Recent data begin to bridge the gap between developmental events controlling
hindbrain neural tube regional patterning and the emergence of breathing
behaviour in the fetus and its vital adaptive function after birth. In
vertebrates, Hox paralogs and Hox-regulating genes orchestrate, in a conserved
manner, the transient formation of developmental compartments in the hindbrain,
the rhombomeres, in which rhythmic neuronal networks of the brainstem develop.
Genetic inactivation of some of these genes in mice leads to pathological
breathing at birth pointing to the vital importance of rhombomere 3 and 4 derived
territories for maintenance of the breathing frequency. In chick embryo at E7, we
investigated neuronal activities generated in neural tube islands deriving from
combinations of rhombomeres isolated at embryonic day E1.5. Using a gain of
function approach, we reveal a role of the transcription factor Krox20,
specifying rhombomeres 3 and 5, in inducing a rhythm generator at the parafacial
level of the hindbrain. The developmental genes selecting and regionally
coordinating the fate of CNS progenitors may hold further clues to conserved
aspects of neuronal network formation and function. However, the most immediate
concern is to take advantage of early generated rhythmic activities in the
hindbrain to pursue their downstream cellular and molecular targets, for it seems
likely that it will be here that rhythmogenic properties will eventually take on
a vital role at birth.
PMID: 16203212 [Indexed for MEDLINE]