Hierarchical Deployment of Factors Regulating Temporal Fate in a Diverse Neuronal Lineage of the Drosophila Central Brain

• Published in: Neuron (Cambridge, Mass.) Vol. 73; no. 4; pp. 677 - 684
• Main Authors: Kao, Chih-Fei, Yu, Hung-Hsiang, He, Yisheng, Kao, Jui-Chun, Lee, Tzumin
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 23.02.2012
• Subjects: Animals; Animals, Genetically Modified; Body Patterning; Brain - cytology; Cell Lineage - genetics; Cell Lineage - physiology; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Drosophila melanogaster; Drosophila melanogaster - cytology; Drosophila melanogaster - embryology; Drosophila melanogaster - genetics; Drosophila Proteins - genetics; Drosophila Proteins - metabolism; Gene Expression Regulation, Developmental - genetics; Gene Expression Regulation, Developmental - physiology; Homeodomain Proteins - genetics; Homeodomain Proteins - metabolism; Kruppel-Like Transcription Factors - genetics; Kruppel-Like Transcription Factors - metabolism; Mutation - genetics; Nerve Tissue Proteins - genetics; Neurons - physiology; POU Domain Factors - genetics; POU Domain Factors - metabolism; Signal Transduction - genetics; Signal Transduction - physiology; Transcription Factors - metabolism
• ISSN: 0896-6273; 1097-4199
• DOI: 10.1016/j.neuron.2011.12.018

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. ► Multiple factors and mechanisms orchestrate neuronal temporal fate specification ► Kr acts alone in the absence of Hb/Pdm/Cas to define one out of 40 temporal fates ► Chinmo acts in the offspring to refine neuronal temporal identity Birth order/time-dependent cell-fate specification requires the orchestrated functions of distinct temporal fating factors. In this study, Kao et al. identified a distinct hierarchical usage of fating factors in a fully sequenced Drosophila central brain neuronal lineage.