Replication stress alters CENP-A nucleosome stability during S phase.

Area of Science:

• Cell Biology
• Epigenetics
• Molecular Biology

Background:

• Centromere identity is epigenetically maintained by CENP-A, crucial for chromosome segregation.
• HJURP chaperone facilitates CENP-A retention during DNA replication.
• Replication stress can disrupt histone chaperone networks, impacting centromere stability.

Purpose of the Study:

• Investigate the impact of replication stress on centromere inheritance.
• Identify proteins involved in maintaining centromeric chromatin stability under stress.
• Elucidate the role of the DAXX-ATRX complex in centromere inheritance.

Main Methods:

• Proximity labeling coupled with affinity purification mass spectrometry to identify centromere-associated proteins.
• Analysis of protein enrichment under replication stress conditions.
• Depletion studies of ATRX and DAXX to assess their role in CENP-A retention.

Main Results:

• Replication stress leads to enrichment of SWI/SNF chromatin remodeling proteins, including ATRX, at CENP-A chromatin.
• Depletion of ATRX and its associated chaperone DAXX causes loss of CENP-A retention during S-phase.
• This loss of CENP-A persists into the subsequent cell cycle.

Conclusions:

• Replication stress negatively impacts centromeric chromatin instability.
• The DAXX-ATRX complex plays a vital role in maintaining centromere inheritance during DNA replication.
• Findings provide insight into mechanisms preventing centromeric chromatin loss under stress.