Completed Genetics & Molecular Biology Cells, Biochemistry & Physiology

The role of non-histone proteins in chromosome structure and function during mitosis

Funder Wellcome Charity-funded
Recipient organisation University of Edinburgh
Funding £4.0M
Period Apr 2021 — Sept 2025

In plain English

AI plain-English summary

Every time a human cell divides, it must compact two metres of DNA into tidy, rod-shaped chromosomes—and this project will map exactly how a handful of proteins orchestrate that dramatic rearrangement, minute by minute. The problem is that while scientists know the main players—condensin, cohesin, Kif4A, topoisomerase IIα—they do not understand the precise sequence of events that transforms a loose chromatin fibre into a mitotic chromosome. Existing methods cannot track these changes in real time because cells enter division asynchronously. The researcher has built a system that synchronises millions of cells, allowing them to capture snapshots of protein binding and DNA looping every sixty seconds as mitosis begins. If successful, this work will produce the first high-resolution, time-resolved map of how chromosomes are built. That matters because errors in chromosome compaction cause mis-segregation, a hallmark of cancer. The project also opens a new line of inquiry into how RNA molecules help assemble the mitotic chromosome periphery compartment, a structure whose function in chromosome separation is unknown. Finally, by improving methods for isolating human artificial chromosomes without unwanted DNA rearrangements, the research could remove a key obstacle to future synthetic genome efforts. This is fundamental science, but it tackles a process that goes wrong in nearly every cancer cell.

View original technical description
I propose to study how a set of key proteins (condensins I/II, cohesin, Kif4A, topo IIα) mold the chromatin fibre into its characteristic rod-shaped helix of loops in mitosis. Using a transformative system allowing us to obtain cultures entering mitosis with near-perfect synchrony we will adopt an interdisciplinary approach involving genomics (Hi-C, Capture-C, cut&run), proteomics, crosslinking, microscopy and molecular modelling to resolve changes in chromatin fibre and chromosomal protein organisation on a minute-by-minute basis during mitotic entry. Using non-toxic synchrony methods plus acute (and reversible) protein depletion with auxin degrons, we will determine when, where, how and with whom these proteins act to shape mitotic chromosomes. Access to the single copy chicken Z chromosome with its unique-sequence centromere allows us unprecedented mapping of the chromatin folding and protein distribution at a vertebrate centromere during this process. Following our discovery that RNAs mediate assembly of the mitotic chromosome periphery compartment (MCPC) downstream of Ki-67, we will initiate a new research direction identifying the proteins and RNAs involved, and determining their functional significance for chromosome segregation. Lastly, we will optimise methods for isolating human artificial chromosomes (HACs), avoiding unwanted DNA rearrangements that endanger future synthetic genome efforts.

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Researchers

William Earnshaw (EPMC Awardee)

Related Research

Grants with similar aims, by meaning.

The role of non-histone proteins in chromosome structure and function during mitosis.
Rebuilding interphase nuclei into mitotic chromosomes
A proteomic and cell biological approach to understand the molecular mechanisms of meiotic chromosome segregation.
Understanding how different condensin activities regulate mitotic chromosome folding in human cells
Biophysical models of cohesin-mediated 3D genome folding and its role in DNA-based processes

Original classification

Principal Research Fellowship Renewal

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