John Marko: Mechanics, geometry and topology of cell nuclei and metaphase chromosomes

Mon, Oct 14, 2019, 12:00 pm
Location: 
Joseph Henry Room Jadwin Hall
Speaker(s): 
Sponsor(s): 
CPBF an NSF PFC

 I will discuss studies of the mechanics and structure of metaphase chromosomes and nuclei extracted from mammalian cells using glass micropipettes. Using a combination of mechanical, biochemical and genetic approaches we have shown that the metaphase chromosome is a "chromatin gel", without a contiguous protein scaffold, and via SMC2 siRNA experiments, that condensin plays a major role as a "crosslinker". I will also discuss the "loop-extrusion" model for establishment of chromatid structure, with special attention to how it generates compaction of chromosomes along their length, or "lengthwise compaction", and how this provides a mechanism for chromatid and chromosome individualization. I will then describe use of the same general approach to analyze the mechanics of mammalian G1 nuclei. The nucleus shows two distinct mechanical responses: an initial chromatin-dominated elastic behavior, followed by a stiffer, lamin-dominated regime at larger extension. The low-force chromatin-based elasticity can be modulated by changing histone acetylation and methylation, and the morphology of the nucleus is impacted by these changes, with heterochromatinization driving the nucleus to be stiffer and rounder, and with euchromatinization destabilizing nuclear shape.

Aleksandra Walczak: Response in immune repertories

Mon, Oct 21, 2019, 12:00 pm

The immune repertoire responds to a wide variety of pathogenic threats. Immune repertoire sequencing experiments give us insight into the...

Location: Joseph Henry Room Jadwin Hall

Ashley Carter: DNA Folding in Sperm

Mon, Nov 4, 2019, 12:00 pm

In sperm, DNA is tightly compacted to create a small, hydrodynamic sperm head.

Location: Joseph Henry Room Jadwin Hall

Paul Francois: TBD

Mon, Nov 11, 2019, 12:00 pm

Searching for simpler models

Fri, Nov 15, 2019, 9:30 am

Neural network pruning and the lottery ticket hypothesis
Jonathan Frankle, Massachusetts Institute of Technology

Location: The Graduate Center, Skylight Room, 9100. 365 Fifth Avenue, between 34th and 35th Streets, in Manhattan

Marija Zanic: Dynamic Architecture of the Microtubule Cytoskeleton

Mon, Nov 18, 2019, 12:00 pm

Microtubules are active biological polymers known to stochastically switch between phases of growth and shrinkage, a behavior termed ‘dynamic...

Melike Lakadamyali: Super-resolution imaging of cellular organization

Mon, Nov 25, 2019, 12:00 pm
Location: Joseph Henry Room Jadwin Hall

Damon Clark: TBD

Mon, Dec 2, 2019, 12:00 pm
Location: Joseph Henry Room Jadwin Hall

Adaptation

Fri, Dec 6, 2019, 9:30 am

Adaptation and Bayesian forecasting in biological systems
Thierry Mora, École Normale Supérieure and Princeton University...

Location: The Graduate Center, Segal Theater. 365 Fifth Avenue, between 34th and 35th Streets, in Manhattan

Hana El-Samad: TBD

Mon, Dec 9, 2019, 12:00 pm
Location: Joseph Henry Room Jadwin Hall

Navish Wadhwa: TBD

Mon, Dec 16, 2019, 12:00 pm
Location: Joseph Henry Room Jadwin Hall

Dmitry Rinberg: TBD

Mon, Jan 27, 2020, 12:00 pm
Location: Joseph Henry Room Jadwin Hall

Sven van Taeffelen: TBD

Mon, Feb 3, 2020, 12:00 pm
Location: Joseph Henry Room Jadwin Hall