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In Vitro Approaches to Investigate Cell Division and Biological Size Control

Wednesday, April 27, 2022 - 3:00pm to 4:00pm

Speaker

Rebecca Heald, Ph.D.
Professor, Department of Molecular & Cell Biology
University of California, Berkeley

Rebecca Health is a professor of Cell and Developmental Biology. The scientific goal of the Heald Lab is to leverage amphibian systems to elucidate molecular mechanisms of cell division and size control, as well as the contribution of genome size and content to organism physiology. Unique and interdisciplinary approaches take advantage of cytoplasmic extracts prepared from eggs of the frog Xenopus laevis that reconstitute mitotic chromosome condensation and spindle assembly and function in vitro. To study mechanisms of spindle and organelle size control, a smaller, related frog, Xenopus tropicalis, has been used to investigate interspecies scaling, and extracts prepared from fertilized eggs at different stages of embryogenesis to study developmental scaling. This research has provided novel insight into cell division and morphogenesis, processes essential for viability and development, and defective in human diseases such as cancer.

Summary

(This will be a hybrid lecture, in person at Lipsett Amphitheater and on NIH VideoCast.) The scientific goal of my laboratory is to elucidate the molecular mechanisms of cell division and size control. Our interdisciplinary approaches take advantage of in vitro systems, particularly cytoplasmic extracts prepared from eggs of the frog Xenopus laevis that reconstitute mitotic chromosome condensation and spindle assembly in vitro. To study mechanisms of spindle and organelle size control, we have utilized a smaller, related frog, Xenopus tropicalis, to investigate interspecies scaling, and extracts prepared from fertilized eggs at different stages of embryogenesis to study developmental scaling. Our research provides novel insight into cell division and morphogenesis, processes essential for viability and development, and defective in human diseases such as cancer. Current projects focus on two major areas. The first is to elucidate molecular mechanisms that define the architecture of the spindle and mitotic chromosomes. We are studying how these mechanisms generate the diversity of spindle morphologies observed across cell types, and how their alteration contributes to chromosome segregation defects observed in cancer cells and in inviable hybrid frog embryos. The second area is to examine size control mechanisms at the subcellular, cellular and organism levels. We are investigating how mitotic chromosome size scales with cell size, and leveraging ploidy manipulation and a variety of amphibian species to explore relationships among genome size, cell size, embryonic development, and metabolism. Our collaborative research aims to provide new insight into principles of mitosis and size scaling, as well as the molecular basis of variation that contributes to genomic instability and evolution. Aside from research, my goal is to provide a productive and nurturing environment for my group members and leverage my experience and leadership opportunities to enhance diversity, equity, inclusion, and belonging more broadly.

Objectives

To appreciate the power of amphibian systems for investigating molecular mechanisms underlying fundamental biological processes including cell division, size scaling across and within species, physiological effects of genome size, and hybrid incompatibility that underlies speciation.


The page was last updated on Tuesday, April 19, 2022 - 9:17am