TRF2 Protein Interacts with Core Histones to Stabilize Chromosome Ends

Area of Science:

• Molecular Biology
• Genetics
• Cell Biology

Background:

• Mammalian chromosome ends, known as telomeres, are protected by the shelterin complex and higher-order chromatin structures.
• Telomere maintenance is crucial for genomic stability and preventing cellular aging.

Purpose of the Study:

• To investigate the interaction between TRF2, a shelterin component, and core histones.
• To elucidate the role of this interaction in telomere protection and stability.

Main Methods:

• Biochemical assays to confirm TRF2 binding to core histones.
• Analysis of a TRF2 mutant lacking critical arginine residues in its GAR domain.
• Microscopy and DNA damage assays to assess telomere integrity.

Main Results:

• TRF2 directly binds to the globular domain of core histones via its Gly/Arg-rich (GAR) domain.
• Specific arginine residues within the TRF2 GAR domain are essential for histone interaction.
• A TRF2 mutant lacking these arginine residues failed to protect telomeres, leading to rapid shortening and cleavage of telomeric chromatin loops.

Conclusions:

• A novel interaction between the shelterin complex (TRF2) and nucleosomal histones is identified.
• This TRF2-histone interaction is critical for stabilizing telomeres and preventing DNA damage response at chromosome ends.
• The findings reveal a previously unrecognized mechanism for telomere end protection.