The study by a team at Penn State University is the first to produce a detailed working image of an enzyme in the Polycomb Repressive Complex 1-a group that regulates cell development and is associated with many types of cancer.
Enzymes like PRC1 turn on or turn off the activity of genes in a cell by manipulating individual chromosome units called nucleosomes. The Penn State scientists obtained the first crystal structure of a gene-regulation enzyme while it is working on a nucleosome. The image reveals previously unknown information about how the enzyme attaches to its nucleosome target. Scientists had been unable to picture exactly how cancer-related enzymes in the PRC1 group interacted with a nucleosome to control gene activity.
His lab earlier had determined the first structure of another nucleosome-bound protein, RCC1. “This is the second important structure from the Tan lab to date of a nucleosome in complex with a protein known to interact with and modify chromatin behavior, which in turn can influence human gene expression,” said Peter Preusch, Ph.D., of the National Institutes of Health’s National Institute of General Medical Sciences, which partially funded the research.
Like PRC1, BRCA1 is a chromatin enzyme that shares a similar activity on the nucleosome.