@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 {65669, title = {A programmable sequence of reporters for lineage analysis.}, journal = {Nature Neuroscience}, volume = {23}, year = {2020}, month = {2020 Dec 01}, pages = {1618-28}, abstract = {

We present CLADES (cell lineage access driven by an edition sequence), a technology for cell lineage studies based on CRISPR-Cas9 techniques. CLADES relies on a system of genetic switches to activate and inactivate reporter genes in a predetermined order. Targeting CLADES to progenitor cells allows the progeny to inherit a sequential cascade of reporters, thereby coupling birth order to reporter expression. This system, which can also be temporally induced by heat shock, enables the temporal resolution of lineage development and can therefore be used to deconstruct an extended cell lineage by tracking the reporters expressed in the progeny. When targeted to the germ line, the same cascade progresses across animal generations, predominantly marking each generation with the corresponding combination of reporters. CLADES therefore offers an innovative strategy for making programmable cascades of genes that can be used for genetic manipulation or to record serial biological events.

}, issn = {1546-1726}, doi = {10.1038/s41593-020-0676-9}, author = {Garcia-Marques, Jorge and Isabel Espinosa Medina and Ku, Kai-Yuan and Yang, Ching-Po and Koyama, Minoru and Yu, Hung-Hsiang and Lee, Tzumin} } @article {6284, title = {Clonal development and organization of the adult Drosophila central brain.}, journal = {Current biology : CB}, volume = {23}, year = {2013}, month = {2013 Apr 22}, pages = {633-43}, abstract = {BACKGROUND: The insect brain can be divided into neuropils that are formed by neurites of both local and remote origin. The complexity of the interconnections obscures how these neuropils are established and interconnected through development. The Drosophila central brain develops from a fixed number of neuroblasts (NBs) that deposit neurons in regional clusters. RESULTS: By determining individual NB clones and pursuing their projections into specific neuropils, we unravel the regional development of the brain neural network. Exhaustive clonal analysis revealed 95 stereotyped neuronal lineages with characteristic cell-body locations and neurite trajectories. Most clones show complex projection patterns, but despite the complexity, neighboring clones often coinnervate the same local neuropil or neuropils and further target a restricted set of distant neuropils. CONCLUSIONS: These observations argue for regional clonal development of both neuropils and neuropil connectivity throughout the Drosophila central brain.}, issn = {1879-0445}, doi = {10.1016/j.cub.2013.02.057}, author = {Yu, Hung-Hsiang and Awasaki, Takeshi and Schroeder, Mark David and Long, Fuhui and Yang, Jacob S and He, Yisheng and Ding, Peng and Kao, Jui-Chun and Wu, Gloria Yueh-Yi and Peng, Hanchuan and Myers, Gene and Lee, Tzumin} } @article {6277, title = {Diverse neuronal lineages make stereotyped contributions to the Drosophila locomotor control center, the central complex.}, journal = {The Journal of Comparative Neurology}, volume = {521}, year = {2013}, month = {2013 Aug 15}, pages = {2645-62, Spc1}, abstract = {

The Drosophila central brain develops from a fixed number of neuroblasts. Each neuroblast makes a clone of neurons that exhibit common trajectories. Here we identified 15 distinct clones that carry larval-born neurons innervating the Drosophila central complex (CX), which consists of four midline structures including the protocerebral bridge (PB), fan-shaped body (FB), ellipsoid body (EB), and noduli (NO). Clonal analysis revealed that the small-field CX neurons, which establish intricate projections across different CX substructures, exist in four isomorphic groups that respectively derive from four complex posterior asense-negative lineages. In terms of the region-characteristic large-field CX neurons, we found that two lineages make PB neurons, 10 lineages produce FB neurons, three lineages generate EB neurons, and two lineages yield NO neurons. The diverse FB developmental origins reflect the discrete input pathways for different FB subcompartments. Clonal analysis enlightens both development and anatomy of the insect locomotor control center.

}, issn = {1096-9861}, doi = {10.1002/cne.23339}, author = {Yang, Jacob S and Awasaki, Takeshi and Yu, Hung-Hsiang and He, Yisheng and Ding, Peng and Kao, Jui-Chun and Lee, Tzumin} } @article {4590, title = {Hierarchical deployment of factors regulating temporal fate in a diverse neuronal lineage of the Drosophila central brain.}, journal = {Neuron}, volume = {73}, year = {2012}, month = {2012 Feb 23}, pages = {677-84}, abstract = {

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.

}, issn = {1097-4199}, doi = {10.1016/j.neuron.2011.12.018}, author = {Kao, Chih-Fei and Yu, Hung-Hsiang and He, Yisheng and Kao, Jui-Chun and Lee, Tzumin} } @article {6290, title = {Lineage analysis of Drosophila lateral antennal lobe neurons reveals notch-dependent binary temporal fate decisions.}, journal = {PLoS Biology}, volume = {10}, year = {2012}, month = {2012 Nov 20}, pages = {e1001425}, abstract = {

Binary cell fate decisions allow the production of distinct sister neurons from an intermediate precursor. Neurons are further diversified based on the birth order of intermediate precursors. Here we examined the interplay between binary cell fate and birth-order-dependent temporal fate in the Drosophila lateral antennal lobe (lAL) neuronal lineage. Single-cell mapping of the lAL lineage by twin-spot mosaic analysis with repressible cell markers (ts-MARCM) revealed that projection neurons (PNs) and local interneurons (LNs) are made in pairs through binary fate decisions. Forty-five types of PNs innervating distinct brain regions arise in a stereotyped sequence; however, the PNs with similar morphologies are not necessarily born in a contiguous window. The LNs are morphologically less diverse than the PNs, and the sequential morphogenetic changes in the two pairs occur independently. Sanpodo-dependent Notch activity promotes and patterns the LN fates. By contrast, Notch diversifies PN temporal fates in a Sanpodo-dispensable manner. These pleiotropic Notch actions underlie the differential temporal fate specification of twin neurons produced by common precursors within a lineage, possibly by modulating postmitotic neurons{\textquoteright} responses to Notch-independent transcriptional cascades.

}, keywords = {Animals, Biological Markers, Brain, Cell Division, Cell Lineage, Cellular, Developmental, Drosophila, Drosophila Proteins, Embryo, Gene Expression Regulation, Genes, Immunohistochemistry, Insect, Larva, Mechanotransduction, Nerve Tissue Proteins, Neurogenesis, Neurons, Nonmammalian, Notch, Receptors, Single-Cell Analysis}, issn = {1545-7885}, doi = {10.1371/journal.pbio.1001425}, author = {Lin, Suewei and Kao, Chih-Fei and Yu, Hung-Hsiang and Huang, Yaling and Lee, Tzumin} } @article {783, title = {A complete developmental sequence of a Drosophila neuronal lineage as revealed by twin-spot MARCM.}, journal = {PLoS Biology}, volume = {8}, year = {2010}, month = {2010 Aug 24}, abstract = {

Drosophila brains contain numerous neurons that form complex circuits. These neurons are derived in stereotyped patterns from a fixed number of progenitors, called neuroblasts, and identifying individual neurons made by a neuroblast facilitates the reconstruction of neural circuits. An improved MARCM (mosaic analysis with a repressible cell marker) technique, called twin-spot MARCM, allows one to label the sister clones derived from a common progenitor simultaneously in different colors. It enables identification of every single neuron in an extended neuronal lineage based on the order of neuron birth. Here we report the first example, to our knowledge, of complete lineage analysis among neurons derived from a common neuroblast that relay olfactory information from the antennal lobe (AL) to higher brain centers. By identifying the sequentially derived neurons, we found that the neuroblast serially makes 40 types of AL projection neurons (PNs). During embryogenesis, one PN with multi-glomerular innervation and 18 uniglomerular PNs targeting 17 glomeruli of the adult AL are born. Many more PNs of 22 additional types, including four types of polyglomerular PNs, derive after the neuroblast resumes dividing in early larvae. Although different offspring are generated in a rather arbitrary sequence, the birth order strictly dictates the fate of each post-mitotic neuron, including the fate of programmed cell death. Notably, the embryonic progenitor has an altered temporal identity following each self-renewing asymmetric cell division. After larval hatching, the same progenitor produces multiple neurons for each cell type, but the number of neurons for each type is tightly regulated. These observations substantiate the origin-dependent specification of neuron types. Sequencing neuronal lineages will not only unravel how a complex brain develops but also permit systematic identification of neuron types for detailed structure and function analysis of the brain.

}, keywords = {Animals, Brain, Cell Lineage, Clone Cells, Drosophila, Genetic Techniques, Mosaicism, Neurogenesis, Neurons, Olfactory Pathways}, issn = {1545-7885}, doi = {10.1371/journal.pbio.1000461}, author = {Yu, Hung-Hsiang and Kao, Chih-Fei and He, Yisheng and Ding, Peng and Kao, Jui-Chun and Lee, Tzumin} } @article {796, title = {Endodomain diversity in the Drosophila Dscam and its roles in neuronal morphogenesis.}, journal = {The Journal of Neuroscience: The Official Journal of the Society for Neuroscience}, volume = {29}, year = {2009}, month = {2009 Feb 11}, pages = {1904-14}, abstract = {

Drosophila Down syndrome cell adhesion molecule (Dscam) can be variably spliced to encode 152,064 distinct single-pass transmembrane proteins. In addition to 19,008 possible ectodomains and two alternative transmembrane segments, it may carry endodomains containing or lacking exons 19 and 23. Here, we determine the role of Dscam endodomain diversity in neural development. Dscam with full-length endodomain is largely restricted to embryogenesis. In contrast, most Dscams lack exons 19 and 23 at postembryonic stages. As implicated from the expression patterns, removal of Dscam exon 19-containing variants disrupts wiring of embryonic neurons while silencing of Dscam transcripts lacking exon 19 or exon 23 effectively blocks postembryonic neuronal morphogenesis. Furthermore, compared with exon 19-containing Dscam, transgenic Dscam without exon 19 is more efficiently targeted to neurites and more potently suppresses axon bifurcation in Dscam mutant neurons. In sum, Dscam with or without exon 19 in its endodomain is used to govern different stage-specific neuronal morphogenetic processes, possibly due to differences in protein targeting.

}, keywords = {Amino Acid Motifs, Amino Acid Sequence, Animals, Cell Adhesion Molecules, Drosophila, Drosophila Proteins, Gene Targeting, Genetically Modified, Molecular Sequence Data, Morphogenesis, Neurogenesis, Neurons, Protein Structure, Tertiary}, issn = {1529-2401}, doi = {10.1523/JNEUROSCI.5743-08.2009}, author = {Yu, Hung-Hsiang and Yang, Jacob S and Wang, Jian and Huang, Yaling and Lee, Tzumin} } @article {781, title = {Twin-spot MARCM to reveal the developmental origin and identity of neurons.}, journal = {Nature Neuroscience}, volume = {12}, year = {2009}, month = {2009 Jul}, pages = {947-53}, abstract = {

A comprehensive understanding of the brain requires the analysis of individual neurons. We used twin-spot mosaic analysis with repressible cell markers (twin-spot MARCM) to trace cell lineages at high resolution by independently labeling paired sister clones. We determined patterns of neurogenesis and the influences of lineage on neuron-type specification. Notably, neural progenitors were able to yield intermediate precursors that create one, two or more neurons. Furthermore, neurons acquired stereotyped projections according to their temporal position in various brain sublineages. Twin-spot MARCM also permitted birth dating of mutant clones, enabling us to detect a single temporal fate that required chinmo in a sublineage of six Drosophila central complex neurons. In sum, twin-spot MARCM can reveal the developmental origins of neurons and the mechanisms that underlie cell fate.

}, keywords = {Animals, Brain, Cell Lineage, Central Nervous System, Drosophila, Drosophila Proteins, Gene Knockout Techniques, Genetic Techniques, Genetically Modified, Mushroom Bodies, Nerve Tissue Proteins, Neurogenesis, Neurons, RNA Interference, Time Factors}, issn = {1546-1726}, doi = {10.1038/nn.2345}, author = {Yu, Hung-Hsiang and Chen, Chun-Hong and Shi, Lei and Huang, Yaling and Lee, Tzumin} } @article {793, title = {Specific Drosophila Dscam juxtamembrane variants control dendritic elaboration and axonal arborization.}, journal = {The Journal of Neuroscience: The Official Journal of the Society for Neuroscience}, volume = {27}, year = {2007}, month = {2007 Jun 20}, pages = {6723-8}, abstract = {

Drosophila Dscam isoforms are derived from two alternative transmembrane/juxtamembrane domains (TMs) in addition to thousands of ectodomain variants. Using a microRNA-based RNA interference technology, we selectively knocked down different subsets of Dscams containing either the exon 17.1- or exon 17.2-encoding TM. Eliminating Dscam[TM1] reduced Dscam expression but minimally affected postembryonic axonal morphogenesis. In contrast, depleting Dscam[TM2] blocked axon arborization. Further removal of Dscam[TM1] enhanced the loss-of-Dscam[TM2] axonal phenotypes. However, Dscam[TM1] primarily regulates dendritic development, as evidenced by the observations that removing Dscam[TM1] alone impeded elaboration of dendrites and that transgenic Dscam[TM1], but not Dscam[TM2], effectively rescued Dscam mutant dendritic phenotypes in mosaic organisms. These distinct Dscam functions can be attributed to the juxtamembrane regions of TMs that govern dendritic versus axonal targeting of Dscam as well. Together, we suggest that specific Drosophila Dscam juxtamembrane variants control dendritic elaboration and axonal arborization.

}, keywords = {Animals, Axons, Cell Adhesion Molecules, Dendrites, Drosophila, Drosophila Proteins, Genetic Variation, Genetically Modified, Membrane Proteins, Morphogenesis, Neural Cell Adhesion Molecules, Protein Isoforms}, issn = {1529-2401}, doi = {10.1523/JNEUROSCI.1517-07.2007}, author = {Shi, Lei and Yu, Hung-Hsiang and Yang, Jacob S and Lee, Tzumin} }