The cell nucleus – where stochastic processes governs life

The cell nucleus – where stochastic processes governs life

Yuval Garini

Physics Department & Institute of Nanotechnology, Bar Ilan University, Ramat Gan 52900, Israel yuval.garini@biu.ac.il

The cell nucleus is a micro-cosmos. It hosts almost all of the genetic information of the specie, as well as the necessary processors for enabling the translation of the information onto proteins, which are the building blocks of life. Moreover, it is also responsible for a sophisticated control mechanism that occurs in space and time.

The total length of the DNA that encodes ~25,000 genes is about 3 meters long. Together with a viscous soup of enzymes and proteins that are responsible for the structure as well as the metabolism, it forms one of the most complex soft-matter systems in the universe (well, this may be my own conception.)

How can this system be studied? It requires to adopt state of the art biophysical methods that combines optical microscopy and spectroscopy, time-resolved methodology, single molecule techniques, biophysical modeling and the use of stochastic theories.

We will go over the basic concepts of the relevant methods, the theoretical formalism that should be used for its interpretation, as well as some of the latest outcome discoveries on this hot topic.

Using dynamic methods in live cells, my group identified a mechanism that maintains the genome organization in the nucleus. It is based on the function of protein called lamin A. We use advanced methods for studying the dynamics of chromatin and proteins in the nucleus. These methods are based on measuring the signal and fluctuations of fluorescent molecules and the use of biophysical models and stochastic theories.

In order to confirm our findings, we also use single-molecule methods including tethered particle motion (TPM) and atomic force microscopy (AFM) to show the type of bonds formed by lamin A and demonstrate the actual bonding that lamin A forms on the DNA.