Large Scale Chromosome Folding Is Stable against Local Changes in Chromatin Structure

Area of Science:

• Biophysics
• Molecular Biology
• Genomics

Background:

• Understanding interphase chromosome folding is crucial for gene transcription.
• The relationship between small-scale chromatin structure and large-scale chromosome organization is not well understood.

Purpose of the Study:

• To investigate the influence of sequence disorder on chromosome spatial and temporal organization using a biophysical model.
• To explore the length and time scales of chromatin conformational changes.

Main Methods:

• Developed a simple biophysical model of interphase chromosomes based on folding chromatin sequences.
• Utilized extensive computer simulations to analyze chromosome behavior.
• Modeled experimental Fluorescence In Situ Hybridization (FISH) data from murine chromosomes.

Main Results:

• Demonstrated that significant chromosome conformational changes are limited to length scales below 10^5 basepairs and time scales under a few seconds.
• Identified potential effective upper bounds for detecting chromosome reorganization in eukaryotic cells.
• Validated the model's relevance by accurately reproducing experimental FISH data.

Conclusions:

• Chromatin sequence disorder plays a role in chromosome folding dynamics.
• The study provides a framework for understanding chromosome organization at different scales.
• Findings suggest limitations in observing large-scale chromosome reorganization in real-time.