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Programmed transformations in neuroblast gene expression during Drosophila CNS lineage development.
1Neurogenetics Unit, Laboratory of Neurochemistry, NINDS, National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892, USA.
Developmental Biology
|September 20, 2000
Summary
Drosophila neuroblast (NB) gene expression transitions, not external signals, generate temporal expression domains (Hunchback, Pdm, Castor, Grainyhead) during CNS development. These sequential changes mark developing neural lineages.
Area of Science:
- Developmental Biology
- Neuroscience
- Genetics
Background:
- Drosophila embryonic central nervous system (CNS) development relies on a transcription factor network.
- Sequential expression of Hunchback (Hb), Pdm, and Castor (Cas) defines temporal identity in neuroblasts (NBs).
- Hb and Cas repressors restrict Pdm expression, creating distinct cellular domains.
Purpose of the Study:
- To investigate the cellular mechanisms underlying the generation of temporal gene expression domains in Drosophila NBs.
- To understand how expression compartments of Hb, Pdm, and Cas are established during development.
Main Methods:
- Studied lineage development of isolated Drosophila NBs in culture.
- Analyzed gene expression transitions and protein perdurance within NB sublineages.
Main Results:
- Hb, Pdm, and Cas expression domains arise from sequential NB gene expression transitions.
- Gene products persist within sequentially produced sublineages, maintaining expression domains.
- Grainyhead (Gh) marks terminal embryonic CNS lineages after Castor expression.
- No further signaling is required for temporal progression after NB lineage initiation.
Conclusions:
- Temporal progression of gene expression (Hb --> Pdm --> Cas --> Gh) in Drosophila NBs is internally regulated.
- Cellular mechanisms involve gene expression transitions and protein perdurance within lineages.
- Grainyhead acts as a terminal marker for embryonic CNS lineages.