Greig LC, Woodworth MB, Poulopoulos A, Lim S, Macklis JD. 2023. BEAM: a combinatorial recombinase toolbox for binary gene expression and mosaic analysis. bioRxiv : the preprint server for biology. Pubmed: 36824714 DOI:10.1101/2023.02.16.528875


Genetic mosaic analysis, in which mutant cells reside intermingled with wild-type cells, is a powerful experimental approach, but has not been widely used in mice because existing genome-based strategies require complicated and protracted breeding schemes. We have developed an alternative approach termed BEAM (for Binary Expression Aleatory Mosaic) that relies on sparse recombinase activation to generate two genetically distinct, non-overlapping populations of cells for comparative analysis. Following delivery of DNA constructs by transfection or viral transduction, combinatorial recombinase activity generates two distinct populations of cells labeled with either green or red fluorescent protein. Any gene of interest can be mis-expressed or deleted in one population for comparison with intermingled control cells. We have extensively optimized and characterized this system both and , and demonstrate its power for investigating cell autonomy, identifying temporally or spatially aberrant phenotypes, revealing changes in cell proliferation or death, and controlling for procedural variability.

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Photo of Jeffrey D. Macklis

Jeffrey Macklis investigates molecular controls and mechanisms over neuron subtype specification, development, diversity, axon guidance-circuit formation, and pathology in the cerebral cortex. His lab seeks to apply developmental controls toward brain and spinal cord regeneration and directed differentiation for in vitro mechanistic modeling using human assembloids.

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