Drosophila type II neuroblasts (NBs), like mammalian neural stem cells, deposit neurons through intermediate neural progenitors (INPs) that can each produce a series of neurons. Both type II NBs and INPs exhibit age-dependent expression of various transcription factors, potentially specifying an array of diverse neurons by combinatorial temporal patterning. Not knowing which mature neurons are made by specific INPs, however, conceals the actual variety of neuron types and limits further molecular studies. Here we mapped neurons derived from specific type II NB lineages and found that sibling INPs produced a morphologically similar but temporally regulated series of distinct neuron types. This suggests a common fate diversification program operating within each INP that is modulated by NB age to generate slightly different sets of diverse neurons based on the INP birth order. Analogous mechanisms might underlie the expansion of neuron diversity via INPs in mammalian brain.
Author contributions
Y.-C.W. carried out experiments and data analysis. J.S.Y. performed pilot studies. R.J. optimized fly brain immunostaining and confocal imaging. Q.R. assisted data analysis. Y.-J.L. assisted data acquisition. H.L. assisted fly genetics. T.B. and W.F.O. identified stg-14. T.L. conceived the study, designed and coordinated experiments and wrote the manuscript.
Funding
This work was supported by Howard Hughes Medical Institute and National Institutes of Health. Deposited in PMC for release after 6 months.
