Mapping Nucleosome Resolution Chromosome Folding in Yeast by Micro-C

Area of Science:

• Genomics
• Molecular Biology
• Chromatin Biology

Background:

• Understanding genome organization is crucial for deciphering gene regulation.
• Previous chromosome conformation capture techniques lacked nucleosome-level resolution.
• Budding yeast genome folding patterns were not well characterized at high resolution.

Purpose of the Study:

• To develop a high-resolution method for mapping chromosome folding.
• To investigate genome-wide chromosome organization in budding yeast.
• To identify factors involved in yeast genome compaction.

Main Methods:

• Developed Micro-C, a Hi-C based technique using micrococcal nuclease for chromatin fragmentation.
• Generated nucleosome-resolution chromosome folding maps for budding yeast.
• Analyzed Micro-C maps to identify self-associating domains and their boundaries.

Main Results:

• Identified abundant, short self-associating domains in yeast, distinct from mammalian topologically associating domains.
• Found domain boundaries enriched at promoters of highly transcribed genes and RSC-bound regions.
• Confirmed roles for RSC, Ssu72, Mediator, Rtt109, and H4 tail in yeast chromosome folding.

Conclusions:

• Micro-C provides unprecedented detail of eukaryotic genome structure.
• Yeast genome folding involves distinct domain structures regulated by specific proteins.
• Findings illuminate the molecular machinery driving chromosome compaction.