Hierarchical deployment of factors regulating temporal fate in a diverse neuronal lineage of the Drosophila central brain
Department of Neurobiology
Medical Subject Headings
Animals; Animals, Genetically Modified; Body Patterning; Brain; Cell Lineage; DNA-Binding Proteins; Drosophila Proteins; Drosophila melanogaster; Gene Expression Regulation, Developmental; Homeodomain Proteins; Kruppel-Like Transcription Factors; Mutation; Nerve Tissue Proteins; Neurons; POU Domain Factors; Signal Transduction; Transcription Factors
Neuroscience and Neurobiology
The anterodorsal projection neuron lineage of Drosophila melanogaster produces 40 neuronal types in a stereotypic order. Here we take advantage of this complete lineage sequence to examine the role of known temporal fating factors, including Chinmo and the Hb/Kr/Pdm/Cas transcriptional cascade, within this diverse central brain lineage. Kr mutation affects the temporal fate of the neuroblast (NB) itself, causing a single fate to be skipped, whereas Chinmo null only elicits fate transformation of NB progeny without altering cell counts. Notably, Chinmo operates in two separate windows to prevent fate transformation (into the subsequent Chinmo-indenpendent fate) within each window. By contrast, Hb/Pdm/Cas play no detectable role, indicating that Kr either acts outside of the cascade identified in the ventral nerve cord or that redundancy exists at the level of fating factors. Therefore, hierarchical fating mechanisms operate within the lineage to generate neuronal diversity in an unprecedented fashion.
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Citation: Neuron. 2012 Feb 23;73(4):677-84. Link to article on publisher's site