Interplay between Human High Mobility Group Protein 1 and Replication Protein A on Psoralen-Cross-linked DNA

Human high mobility group box (HMGB) 1 and -2 proteins are highly conserved and abundant chromosomal proteins that regulate chromatin structure and DNA metabolism. HMGB proteins bind preferentially to DNA that is bent or underwound and to DNA damaged by agents such as cisplatin, UVC radiation, and b...

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Bibliographic Details
Published in:Biochemistry (Easton) 2005-03, Vol.44 (11), p.4188-4195
Main Authors: Reddy, Madhava C, Christensen, Jesper, Vasquez, Karen M
Format: Article
Language:English
Subjects:
Base Sequence
Binding, Competitive
DNA - metabolism
DNA Damage
DNA Repair
DNA Replication
DNA-Binding Proteins - metabolism
HMGB1 Protein - metabolism
Humans
Molecular Sequence Data
Nucleic Acid Conformation
Nucleic Acid Heteroduplexes - metabolism
Oligonucleotides - metabolism
Protein Binding
Replication Protein A
Trioxsalen - metabolism
Ultraviolet Rays
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Summary:Human high mobility group box (HMGB) 1 and -2 proteins are highly conserved and abundant chromosomal proteins that regulate chromatin structure and DNA metabolism. HMGB proteins bind preferentially to DNA that is bent or underwound and to DNA damaged by agents such as cisplatin, UVC radiation, and benzo[a]pyrenediol epoxide (BPDE). Binding of HMGB1 to DNA adducts is thought to inhibit nucleotide excision repair (NER), leading to cell death, but the biological roles of these proteins remain obscure. We have used psoralen-modified triplex-forming oligonucleotides (TFOs) to direct a psoralen−DNA interstrand cross-link (ICL) to a specific site to determine the effect of HMGB proteins on recognition of these lesions. Our results reveal that human HMGB1 (but not HMGB2) binds with high affinity and specificity to psoralen ICLs, and interacts with the essential NER protein, replication protein A (RPA), at these lesions. RPA, shown previously to bind tightly to these lesions, also binds in the presence of HMGB1, without displacing HMGB1. A discrete ternary complex is formed, containing HMGB1, RPA, and psoralen-damaged DNA. Thus, HMGB1 has the ability to recognize ICLs, can cooperate with RPA in doing so, and likely modulates their repair by the NER machinery. The abundance of HMGB1 suggests that it may play an important role in determining the sensitivity of cells to DNA damage under physiological, experimental, and therapeutic conditions.
ISSN:0006-2960
1520-4995
DOI:10.1021/bi047902n