Fanconi anemia group J mutation abolishes its DNA repair function by uncoupling DNA translocation from helicase activity or disruption of protein-DNA complexes.
Fanconi anemia (FA) is a genetic disease characterized by congenital abnormalities, bone marrow failure, and susceptibility to leukemia and other cancers. FANCJ, one of 13 genes linked to FA, encodes a DNA helicase proposed to operate in homologous recombination repair and replicational stress response. The pathogenic FANCJ-A349P amino acid substitution resides immediately adjacent to a highly conserved cysteine of the iron-sulfur domain. Given the genetic linkage of the FANCJ-A349P allele to FA, we investigated the effect of this particular mutation on the biochemical and cellular functions of the FANCJ protein. Purified recombinant FANCJ-A349P protein had reduced iron and was defective in coupling adenosine triphosphate (ATP) hydrolysis and translocase activity to unwinding forked duplex or G-quadruplex DNA substrates or disrupting protein-DNA complexes. The FANCJ-A349P allele failed to rescue cisplatin or telomestatin sensitivity of a FA-J null cell line as detected by cell survival or γ-H2AX foci formation. Furthermore, expression of FANCJ-A349P in a wild-type background exerted a dominant-negative effect, indicating that the mutant protein interferes with normal DNA metabolism. The ability of FANCJ to use the energy from ATP hydrolysis to produce the force required to unwind DNA or destabilize protein bound to DNA is required for its role in DNA repair.
Wu
Yuliang
Y
Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, National Institutes of Health Biomedical Research Center, Baltimore, MD 21224, USA.
Sommers
Joshua A
JA
Suhasini
Avvaru N
AN
Leonard
Thomas
T
Deakyne
Julianna S
JS
Mazin
Alexander V
AV
Shin-Ya
Kazuo
K
Kitao
Hiroyuki
H
Brosh
Robert M
RM
D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D050976:Basic-Leucine Zipper Transcription Factors / Q000235:genetics* / Q000378:metabolism*; D004247:DNA / Q000378:metabolism; D004265:DNA Helicases / Q000235:genetics / Q000378:metabolism; D004260:DNA Repair / Q000235:genetics* / Q000502:physiology*; D051856:Fanconi Anemia Complementation Group Proteins / Q000235:genetics* / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D007501:Iron / Q000378:metabolism; D016685:Mitomycin / Q000494:pharmacology; D008969:Molecular Sequence Data; D050505:Mutant Proteins / Q000235:genetics* / Q000378:metabolism*; D020125:Mutation, Missense; D010080:Oxazoles / Q000494:pharmacology; D055550:Protein Stability; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism
C102108:BACH1 protein, human; D050976:Basic-Leucine Zipper Transcription Factors; D051856:Fanconi Anemia Complementation Group Proteins; D050505:Mutant Proteins; D010080:Oxazoles; D011994:Recombinant Proteins; C431888:telomestatin; D016685:Mitomycin; D000255:Adenosine Triphosphate; D004247:DNA; D007501:Iron; D000251:Adenosine Triphosphatases; D004265:DNA Helicases