Key protein for cells' gene regulation needs a chaperone to do its job
A protein that's essential to every cell's ability to turn off unnecessary genes is well known for its key function of compacting genes and its connection to cancer when it undergoes mutation. But until now, scientists weren't quite sure how the protein gets where it needs to go to keep genes bound up so they aren't activated.
Linker histone H1, a critical protein for gene regulation, requires a chaperone protein to effectively compact DNA and inhibit gene expression. Until recently, scientists were unsure how the protein reached its target within the cell. Researchers found that H1 initially moves freely inside cells, even in the presence of its target, a nucleosome containing wrapped DNA segments.
Upon binding to DNA, H1 struggles to attach to the nucleosome itself until a chaperone protein assists. Using single-molecule experiments, scientists observed H1's movement and its interaction with DNA and nucleosomes. They discovered that H1 not only slides along DNA but also needs chaperone proteins to load onto the nucleosome.
This finding clarifies how H1 positions itself to compact chromatin and repress gene expression, offering insights into how H1 dysfunction may contribute to disease development.
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