@article {68067, title = {Hormone-controlled changes in the differentiation state of post-mitotic neurons.}, journal = {Current Biology}, volume = {32}, year = {2022}, month = {2022 May 23}, pages = {2341-2348}, abstract = {

While we think of neurons as having a fixed identity, many show spectacular plasticity. Metamorphosis drives massive changes in the fly brain; neurons that persist into adulthood often change in response to the steroid hormone ecdysone. Besides driving remodeling, ecdysone signaling can also alter the differentiation status of neurons. The three sequentially born subtypes of mushroom body (MB) Kenyon cells (γ, followed by α{\textquoteright}/β{\textquoteright}, and finally α/β) serve as a model of temporal fating. γ neurons are also used as a model of remodeling during metamorphosis. As γ neurons are the only functional Kenyon cells in the larval brain, they serve the function of all three adult subtypes. Correspondingly, larval γ neurons have a similar morphology to α{\textquoteright}/β{\textquoteright} and α/β neurons-their axons project dorsally and medially. During metamorphosis, γ neurons remodel to form a single medial projection. Both temporal fate changes and defects in remodeling therefore alter γ-neuron morphology in similar ways. Mamo, a broad-complex, tramtrack, and bric-{\`a}-brac/poxvirus and zinc finger (BTB/POZ)\ transcription factor critical for temporal specification of α{\textquoteright}/β{\textquoteright} neurons, was recently described as essential for γ remodeling. In a previous study, we noticed a change in the number of adult Kenyon cells expressing γ-specific markers when mamo was manipulated. These data implied a role for Mamo in γ-neuron fate specification, yet mamo is not expressed in γ neurons until pupariation, well past γ specification. This indicates that mamo has a later role in ensuring that γ neurons express the correct Kenyon cell subtype-specific genes in the adult brain.

}, issn = {1879-0445}, doi = {10.1016/j.cub.2022.04.027}, author = {Lai, Yen-Wei and Miyares, Rosa L and Liu, Ling-Yu and Chu, Sao-Yu and Lee, Tzumin and Yu, Hung-Hsiang} } @article {65622, title = {Enhanced Golic+: Highly effective CRISPR gene targeting and transgene HACKing in .}, journal = {Development}, year = {2020}, month = {2020 May 28}, abstract = {

Gene targeting is an incredibly valuable technique. Sometimes however, it can also be extremely challenging for various intrinsic reasons (e.g. low target accessibility or nature/extent of gene modification). To bypass these barriers, we designed a transgene-based system in Drosophila that increases the number of independent gene targeting events while at the same time enriching for correctly targeted progeny. Unfortunately, with particularly challenging gene targeting experiments, our original design yielded numerous false positives. Here we deliver a much-improved technique named Enhanced Golic+ (E-Golic+). E-Golic+ incorporates genetic modifications to tighten lethality-based selection while simultaneously boosting efficiency. With E-Golic+, we easily achieve previously unattainable gene targeting. Additionally, we built an E-Golic+ based, high-efficiency genetic pipeline for transgene swapping. We demonstrate its utility by transforming GAL4 enhancer-trap lines into tissue-specific Cas9-expressing lines. Given the superior efficiency, specificity and scalability, E-Golic+ promises to expedite development of additional sophisticated genetic/genomic tools in .

}, issn = {1477-9129}, doi = {10.1242/dev.181974}, author = {Chen, Hui-Min and Yao, Xiaohao and Ren, Qingzhong and Chang, Chuan-Chie and Liu, Ling-Yu and Miyares, Rosa Linda and Lee, Tzumin} } @article {65160, title = {Mamo decodes hierarchical temporal gradients into terminal neuronal fate.}, journal = {Elife}, volume = {8}, year = {2019}, month = {2019 Sep 23}, abstract = {

Temporal patterning is a seminal method of expanding neuronal diversity. Here we unravel a mechanism decoding neural stem cell temporal gene expression and transforming it into discrete neuronal fates. This mechanism is characterized by hierarchical gene expression. First, neuroblasts express opposing temporal gradients of RNA-binding proteins, Imp and Syp. These proteins promote or inhibit translation, yielding a descending neuronal gradient. Together, first and second-layer temporal factors define a temporal expression window of BTB-zinc finger nuclear protein, Mamo. The precise temporal induction of Mamo is achieved via both transcriptional and post-transcriptional regulation. Finally, Mamo is essential for the temporally defined, terminal identity of α{\textquoteright}/β{\textquoteright} mushroom body neurons and identity maintenance. We describe a straightforward paradigm of temporal fate specification where diverse neuronal fates are defined via integrating multiple layers of gene regulation. The neurodevelopmental roles of orthologous/related mammalian genes suggest a fundamental conservation of this mechanism in brain development.

}, issn = {2050-084X}, doi = {10.7554/eLife.48056}, author = {Liu, Ling-Yu and Long, Xi and Yang, Ching-Po and Miyares, Rosa L and Sugino, Ken and Singer, Robert H and Lee, Tzumin} } @article {47307, title = {Transcriptomes of lineage-specific Drosophila neuroblasts profiled by genetic targeting and robotic sorting.}, journal = {Development (Cambridge, England)}, volume = {143}, year = {2016}, month = {2016 Feb 1}, pages = {411-21}, abstract = {

A brain consists of numerous distinct neurons arising from a limited number of progenitors, called neuroblasts in Drosophila. Each neuroblast produces a specific neuronal lineage. To unravel the transcriptional networks that underlie the development of distinct neuroblast lineages, we marked and isolated lineage-specific neuroblasts for RNA sequencing. We labeled particular neuroblasts throughout neurogenesis by activating a conditional neuroblast driver in specific lineages using various intersection strategies. The targeted neuroblasts were efficiently recovered using a custom-built device for robotic single-cell picking. Transcriptome analysis of mushroom body, antennal lobe and type II neuroblasts compared with non-selective neuroblasts, neurons and glia revealed a rich repertoire of transcription factors expressed among neuroblasts in diverse patterns. Besides transcription factors that are likely to be pan-neuroblast, many transcription factors exist that are selectively enriched or repressed in certain neuroblasts. The unique combinations of transcription factors present in different neuroblasts may govern the diverse lineage-specific neuron fates.

}, issn = {1477-9129}, doi = {10.1242/dev.129163}, author = {Yang, Ching-Po and Fu, Chi-Cheng and Sugino, Ken and Liu, Zhiyong and Ren, Qingzhong and Liu, Ling-Yu and Yao, Xiaohao and Lee, Luke P and Lee, Tzumin} } @article {47126, title = {Opposing intrinsic temporal gradients guide neural stem cell production of varied neuronal fates.}, journal = {Science (New York, N.Y.)}, volume = {350}, year = {2015}, month = {2015 Oct 16}, pages = {317-20}, abstract = {

Neural stem cells show age-dependent developmental potentials, as evidenced by their production of distinct neuron types at different developmental times. Drosophila neuroblasts produce long, stereotyped lineages of neurons. We searched for factors that could regulate neural temporal fate by RNA-sequencing lineage-specific neuroblasts at various developmental times. We found that two RNA-binding proteins, IGF-II mRNA-binding protein (Imp) and Syncrip (Syp), display opposing high-to-low and low-to-high temporal gradients with lineage-specific temporal dynamics. Imp and Syp promote early and late fates, respectively, in both a slowly progressing and a rapidly changing lineage. Imp and Syp control neuronal fates in the mushroom body lineages by regulating the temporal transcription factor Chinmo translation. Together, the opposing Imp/Syp gradients encode stem cell age, specifying multiple cell fates within a lineage.

}, issn = {1095-9203}, doi = {10.1126/science.aad1886}, author = {Liu, Zhiyong and Yang, Ching-Po and Sugino, Ken and Fu, Chi-Cheng and Liu, Ling-Yu and Yao, Xiaohao and Lee, Luke P and Lee, Tzumin} }