First published online July 10, 2007
Development 134, 1503e (2007)
© The Company of Biologists Limited
Helt! Who goes there?
GABAergic and glutamatergic neurons are the principal inhibitory and
excitatory neurons in the brain, respectively. Selector genes that determine
which neurotransmitter phenotype a neuron adopts during development have been
identified for some regions of the brain. Now, Nakatani and colleagues report
that the basic helix-loop-helix (bHLH) transcriptional repressor gene
Helt (also known as Heslike and Megane) promotes
GABAergic fate throughout the developing mouse midbrain by repressing the
proneural Ngn genes (see p.
2783). The researchers show that glutamatergic neurons replace
GABAergic neurons in the midbrain of Helt-deficient mice. Ectopic
expression of Helt, they report, has the opposite effect. Neither
Helt manipulation, however, affects progenitor domain formation,
which indicates that Helt does not specify neuronal identity. In
other experiments, the researchers show that Helt promotes a
GABAergic fate by suppressing the expression of Ngn1 and
Ngn2, bHLH factors that are expressed in glutamatergic progenitors.
Thus, they conclude, a bHLH transcription factor network determines the
neurotransmitter phenotype of neurons in the midbrain.
Related articles in Development:
- Helt determines GABAergic over glutamatergic neuronal fate by repressing Ngn genes in the developing mesencephalon
- Tomoya Nakatani, Yasuko Minaki, Minoru Kumai, and Yuichi Ono
Development 2007 134: 2783-2793.
[Abstract]
[Full Text]
