Event
Bioengineering Seminar Series: Kris Dahl
Friday, February 22, 2013
11:00 a.m.-12:00 p.m.
Room 1200, Jeong H. Kim Engineering Building
Professor Ian White
ianwhite@umd.edu
Nuclear Mechanics and Regulation of Cell Phenotype
Kris Dahl
Associate Professor
Chemical and Biomedical Engineering
Carnegie Mellon University
The sequencing of the human genome has provided a wealth of scientific information, but this information is limited by the poor understanding of the mechanisms which control gene expression. The genome within the nucleus is a complex, self-assembled polymeric structure with unique rheological properties. The structure and mechanics of the nucleus is altered in cells undergoing phenotypic changes. For example, cells with a broader spectrum of gene expression patterns, including stem cells and cancer cells, have much softer nuclei whereas aged cells have stiffer nuclei. We measure the mechanics of these different cell types, and we also examine the role that force and cytokine treatment play in altering nuclear mechanics and gene expression. Motor activity from the cytoskeleton impact the driving force for nuclear and subnuclear movement, and altered chromatin condensation shifts the resistance and propagation of forces. The mechanics of the nuclear interior is capable of responding proportionally to mechanical and chemical stimuli. We find distinct temporal regimes of subnuclear movements as nuclei adapt to applied force by stiffening. Thus, nuclear structure and mechanics may be an important regulatory factor in directing or modulating global changes in gene expression.
