Discovery finds a cellular building block acts as a gel, not liquid as previously believed

Phys.org ^ | 12/18/2020 | University of Alberta Faculty of Medicine & Dentistry

[BenLurkin]

Previously, fields such as biochemistry operated under the assumption that chromatin and other elements of the nucleus operated in a liquid state... This new understanding of the physical properties of chromatin challenges that idea, and could lead to a more accurate understanding of how the genome is encoded and decoded.

All of our chromosomes are made from chromatin, which is half histone (or structural) proteins and half DNA, organized into long strings with bead-like structures (nucleosomes) on them. Inside the nucleus of a cell, the chromatin fiber interacts with itself to condense into a chromosome. The chromatin fiber also supports gene expression and replication of chromosomal DNA. Although there is some understanding of the structures that make up a nucleus, how those structures are organized and the full extent of how the structures interact with each other is not well known.

The team's findings bridge research done over the past 50 years on chromatin gels produced in the laboratory to demonstrate its existence in living cells, which has major implications for interpreting their elastic and mechanical properties, Hendzel explained.

For example, recent studies have shown that the deformability of chromatin in cancer cells is an important determinant of their ability to squeeze through small spaces to travel outside a tumor and metastasize elsewhere in the body—something that is much easier to explain if chromatin is gel-like rather than a liquid. Cancer cells do that by chemically changing the histone part of the chromatin to make it less sticky, Hendzel said.

Based on the new research, this can now be explained as a process that reduces the strength of the gel, making it more deformable and enabling cancer cells to spread through the body.

[Honorary Serb]

Chromatin extracted from cells in the lab has always been a gel! I know—I’ve extracted it!!! And we’ve know this for decades!!!!