Proceedings of The Physiological Society
King's College London (2011) Proc Physiol Soc 22, C02
From stem cells to inborn behaviour: clonal origin and genetic specification of a motor control centre in Drosophila
Z. Ludlow1, K. E. White1, F. Hirth1
1. MRC Centre for Neurodegeneration Research, Institute of Psychiatry, King's College London, London, United Kingdom.
Inborn behaviours rely on neural circuits that are genetically determined during development. However, it is currently unknown how such circuits are formed. Here we show that stem cell-derived clonal units in the Drosophila brain generate neural circuit elements underlying inborn walking behaviour. Tracing the progeny of embryonic neuroblasts ppd5/8, we found that these neural stem cells give rise to large-field ring neurons of all subtypes, R1-R4, that constitute an entire set of circuit elements intrinsic to the ellipsoid body of the central complex in the adult brain. During development, initial formation of these neural lineages depends on Engrailed function and their maintenance requires FGF8 signalling. Prospero activity limits the number of neuronal progeny and Dscam is involved in ring neuron synaptogenesis, both of which are necessary for correct formation of the ellipsoid body neuropil. A GABAergic subset of these clonally-related cells, comprising R2 and R4 neurons, are required for specific aspects of inborn walking behaviour. Our findings suggest that an inherited genetic program specifies stem cell-derived ontogenetic clones that form functional units of neural circuitry underlying inborn animal behaviour.
Where applicable, experiments conform with Society ethical requirements