hSSB1 (NABP2/OBFC2B) is regulated by oxidative stress

Area of Science:

• Molecular Biology
• Genetics
• Cellular Biology

Background:

• Genome stability is vital for preventing diseases like cancer.
• Human single-stranded DNA-binding protein 1 (hSSB1) is essential for DNA damage response, including double-strand break repair and base excision repair of 8-oxoguanine.
• hSSB1 facilitates the localization of human 8-oxoguanine glycosylase (hOGG1) to damaged DNA sites.

Purpose of the Study:

• To investigate the regulatory mechanism of hSSB1 in DNA repair pathways.
• To determine the role of hSSB1 oligomerization in the repair of oxidative DNA damage.
• To elucidate the specific functions of monomeric versus oligomeric hSSB1.

Main Methods:

• Studying hSSB1 behavior under oxidative stress conditions.
• Assessing the affinity of monomeric and oligomeric hSSB1 for oxidized DNA.
• Evaluating the impact of hSSB1 oligomerization on 8-oxoguanine removal and double-strand break repair.
• Investigating the role of ATM signaling in hSSB1 function.

Main Results:

• Oxidative stress stabilizes hSSB1 as an oligomer, which is essential for 8-oxoguanine removal.
• Monomeric hSSB1 exhibits reduced affinity for oxidized DNA, leading to impaired 8-oxoguanine repair and defective ATM signaling initiation.
• hSSB1 oligomerization is critical for 8-oxoguanine repair but not for homologous recombination repair of double-strand DNA breaks.

Conclusions:

• hSSB1 oligomerization represents a novel regulatory mechanism for DNA repair.
• The oligomeric state of hSSB1 dictates its specific function in different DNA repair pathways.
• Understanding hSSB1 regulation provides insights into preventing diseases associated with DNA damage.