Chromosome cohesion

Dr Nobuaki Kudo and his team are trying to understand how chromosomes are structurally organised and how this influences their functions.

When cells divide, the chromosomes replicate and one of each chromosome is passed into the two daughter cells. About 10 years ago scientists discovered ‘glue proteins’ that connect replicated chromosomes to each other and noticed that these glue proteins are important for controlling how the new chromosomes are allotted to the two daughter cells. We place these glue proteins at the centre of our research programme.

Because of the accurate replication and segregation mechanisms, the cells within our body have identical copies of chromosomes even though our cells from different parts of the body appear and function very differently. The different characteristics of cells are in fact determined by whether individual genes in the chromosomes are read and not.

The chromosome is a linear structure like a thread, but in the cell it is coiled and folded to form enormous numbers of loops. Recent studies discovered that the glue proteins have another role: they contribute to form those loops and control which gene to read and not to read. Importantly, the glue proteins can move onto the chromosomes when the cells change their nature.

We are interested in the specialised cells, called germ cells, which give rise to sperm or eggs. Their chromosomes have many unique features, which are related to the unique developmental potential of the germ cells. For example, germ cells can make a new chromosome for the next generation by a different process, called recombination.

Currently we are trying to identify where, on the chromosomes, the glue proteins bind. This will give us an idea about the unique nature of chromosome structure of germ cells. Then, based on the structural features, we will continue our investigation to understand how and why chromosomes of germ cells can function differently. Our science will be useful to understand the mechanism for many congenital diseases including of Down Syndrome and Cornelia de Lange Syndromes.

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