Genetic mosaics, in which somatic cells of different genotypes reside in the same animal, have been widely used to study biological processes in multicellular organisms. By knocking out a candidate gene of interest in a defined population of cells at a desirable time, one can study gene function in biological processes of interest while bypassing possible requirements for the gene in other tissues or at earlier developmental stages. One can also analyze the cell autonomy of gene function if the candidate gene is removed only in small populations of defined cell types. In addition, mosaic analysis can be used to create animal models for human diseases that result from somatic mutations. We have recently developed a genetic mosaic system in mice termed """"""""MADM"""""""" (for Mosaic Analysis with Double Markers), which allows simultaneous in vivo labeling and genetic manipulation of defined neuronal populations, down to the level of single isolated neurons. We have established MADM at the ROSA26 locus of mouse chromosome 6 to show that 1) inter-chromosomal recombination can occur efficiently the Cre-loxP system;2) MADM can be used to create conditional knockouts in small populations of labeled cells to study gene function;3) MADM can be used to investigate the relationship between neuronal lineage and wiring patterns. We have also preliminary data that MADM can be expanded to other chromosomes using targeted knockin and random ES cell transgenesis approaches. We now propose to expand the MADM system to all mouse chromosomes so that one can perform MADM-based mosaic analysis for vast majority of genes in the mouse. We also propose to use the features afforded by MADM to investigate the role of neuronal activity in morphological maturation of individual neurons and in circuit development. Lastly, we will apply MADM to study several genes implicated in human neurological diseases, including lissencephaly and autism- spectrum disorders.

Public Health Relevance

We propose to expand a technique we developed that allows one to disrupt a gene in small population of well-defined cells in the mouse. Utilizing this technique, we will study how experience in the form of neuronal activity shapes neuronal development and brain wiring, and why certain genes, when mutated in human, cause devastating neurological problems. These studies will have direct implications to our understanding of the pathogenesis of lissencephaly and Smith-Magenis Syndrome.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS050835-08
Application #
8204882
Study Section
Special Emphasis Panel (ZRG1-MNG-B (01))
Program Officer
Mamounas, Laura
Project Start
2005-01-01
Project End
2013-12-31
Budget Start
2012-01-01
Budget End
2012-12-31
Support Year
8
Fiscal Year
2012
Total Cost
$364,909
Indirect Cost
$150,534
Name
Stanford University
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
009214214
City
Stanford
State
CA
Country
United States
Zip Code
94305
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Luo, Liqun; Callaway, Edward M; Svoboda, Karel (2018) Genetic Dissection of Neural Circuits: A Decade of Progress. Neuron 98:256-281
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Lasrado, Reena; Boesmans, Werend; Kleinjung, Jens et al. (2017) Lineage-dependent spatial and functional organization of the mammalian enteric nervous system. Science 356:722-726
Allen, William E; DeNardo, Laura A; Chen, Michael Z et al. (2017) Thirst-associated preoptic neurons encode an aversive motivational drive. Science 357:1149-1155
DeNardo, Laura; Luo, Liqun (2017) Genetic strategies to access activated neurons. Curr Opin Neurobiol 45:121-129
Fran├žois, Amaury; Low, Sarah A; Sypek, Elizabeth I et al. (2017) A Brainstem-Spinal Cord Inhibitory Circuit for Mechanical Pain Modulation by GABA and Enkephalins. Neuron 93:822-839.e6
Wagner, Mark J; Kim, Tony Hyun; Savall, Joan et al. (2017) Cerebellar granule cells encode the expectation of reward. Nature 544:96-100
Allen, William E; Luo, Liqun (2015) Intersectional illumination of neural circuit function. Neuron 85:889-92
Huang, Z Josh; Luo, Liqun (2015) NEUROSCIENCE. It takes the world to understand the brain. Science 350:42-4

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