From GAL4 to targeted DAM-ID: Tools for Studying Gene Expression In Vivo (Andrea Brand)

In this episode, we speak with Andrea Brand, Chair of the Department of Cell Biology at NYU Grossman School of Medicine and Director of the Regenerative Medicine Institute. We discuss her scientific path from yeast gene regulation to Drosophila neurobiology, and how early interests in DNA and microscopy shaped her career.

We talk about the development of the GAL4 system with Norbert Perrimon and how it enabled targeted gene expression in specific tissues and cells. Andrea explains why this approach has remained useful across decades, including its applications in Drosophila and beyond, while noting that no experimental system is perfect and results should be cross-checked with other methods.

We also discuss targeted DAM-ID and chromatin DAM-ID, methods developed in her lab to study protein-DNA interactions and chromatin marks in vivo without removing cells from their normal tissue environment. Andrea describes how these tools helped her lab analyze neural stem cells in their niche and investigate changes in chromatin during quiescence and reactivation.

A major theme of the conversation is neural stem cell quiescence. We cover how her lab found that quiescent stem cells can show unexpectedly open chromatin, express neuronal genes, and adopt neuron-like features, including long projections and interactions with neurons. We also discuss the link to metabolism, including feeding signals, the fat body, blood-brain barrier glia, insulin-like peptides, and TGF-beta signaling.

Finally, we talk about Andrea’s recent move toward human brain organoids and the goal of connecting model organism work to human biology and patient data. We discuss ongoing work on quiescent cells, TRIB family genes, and cancer–neuron interactions, as well as the need to better distinguish quiescence from senescence in vivo.

References

• Brand, A. H., & Perrimon, N. (1993). Targeted gene expression as a means of altering cell fates and generating dominant phenotypes. Development (Cambridge, England), 118(2), 401–415. https://doi.org/10.1242/dev.118.2.401
• Southall, T. D., Gold, K. S., Egger, B., Davidson, C. M., Caygill, E. E., Marshall, O. J., & Brand, A. H. (2013). Cell-type-specific profiling of gene expression and chromatin binding without cell isolation: assaying RNA Pol II occupancy in neural stem cells. Developmental cell, 26(1), 101–112. https://doi.org/10.1016/j.devcel.2013.05.020
• Tang, J. L. Y., Hakes, A. E., Krautz, R., Suzuki, T., Contreras, E. G., Fox, P. M., & Brand, A. H. (2022). NanoDam identifies Homeobrain (ARX) and Scarecrow (NKX2.1) as conserved temporal factors in the Drosophila central brain and visual system. Developmental cell, 57(9), 1193–1207.e7. https://doi.org/10.1016/j.devcel.2022.04.008
• Cheetham, S. W., & Brand, A. H. (2018). RNA-DamID reveals cell-type-specific binding of roX RNAs at chromatin-entry sites. Nature structural & molecular biology, 25(1), 109–114. https://doi.org/10.1038/s41594-017-0006-4
• Cheetham, S. W., Gruhn, W. H., van den Ameele, J., Krautz, R., Southall, T. D., Kobayashi, T., Surani, M. A., & Brand, A. H. (2018). Targeted DamID reveals differential binding of mammalian pluripotency factors. Development (Cambridge, England), 145(20), dev170209. https://doi.org/10.1242/dev.170209

Related Episodes

• scDamID, EpiDamID and Lamina Associated Domains (Jop Kind)
• Characterizing Chromatin at the Nuclear Lamina (Bas van Steensel)

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