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  • Developmental biology
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Published online: 16 July 2008 | doi:10.1038/nchina.2008.162

Neurogenesis: Control factors

Felix Cheung

Introduction

© (2008) Elsevier

The dorsal spinal cord (the back side of the spinal cord) carries sensory information from the body to the brain. It houses two types of neurons: excitatory neurons, which use glutamate as neurotransmitters for sending the information; and inhibitory neurons, which use gamma-aminobutyric acid (GABA) or glycine as neurotransmitters for modulating the information flow of excitatory neurons. There are also inhibitory neurons that synthesize peptide transmitters. Leping Cheng and co-workers at the Chinese Academy of Sciences in Shanghai¹ have uncovered the roles of three transcription factors in regulating which type of inhibitory neurons are produced during neural development.

Previous studies have identified that Ptf1a, Pax2 and Lbx1 regulate the production of GABA-type neurons. The researchers examined whether these transcription factors are also essential for the production of glycine-type and peptide-type neurons. They injected vectors that express Ptf1a, Pax2 or Lbx1 into the neural tube of chicken embryos at the mid stage of neurogenesis. The embryos were allowed to grow for a further 48 hours — late-stage neurogenesis.

Compared with normal chick embryos (see left image), glycine-type neurons of chick embryos that lacked Ptf1a (see right image), Pax2 or Lbx1 expression vectors were virtually eliminated from the dorsal (marked by an arrow) but not the ventral, that is, the belly side of the spinal cord (marked by arrowheads).

Further experiments showed that Ptf1a is a master regulator of the production of glycine-type and peptide-type neurons, whereas Pax2 and Lbx1 control different subsets of neuron types. The findings will help scientists understand the genetic basis of the tremendous diversity in dorsal spinal inhibitory neurons.

The authors of this work are from:
Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.

Reference

1. Huang, M. et al. Ptf1a, Lbx1 and Pax2 coordinate glycinergic and peptidergic transmitter phenotypes in dorsal spinal inhibitory neurons. Dev. Biol. doi: 10.1016/j.ydbio.2008.06.031 (2008). | Article |