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- Elliott, Kerryn, et al.
(författare)
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Base-resolution UV footprinting by sequencing reveals distinctive damage signatures for DNA-binding proteins
- 2023
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Ingår i: Nature Communications. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Decades ago, it was shown that proteins binding to DNA can quantitatively alter the formation of DNA damage by UV light. This established the principle of UV footprinting for non-intrusive study of protein-DNA contacts in living cells, albeit at limited scale and precision. Here, we perform deep base-resolution quantification of the principal UV damage lesion, the cyclobutane pyrimidine dimer (CPD), at select human promoter regions using targeted CPD sequencing. Several transcription factors exhibited distinctive and repeatable damage signatures indicative of site occupancy, involving strong (up to 17-fold) position-specific elevations and reductions in CPD formation frequency relative to naked DNA. Positive damage modulation at some ETS transcription factor binding sites coincided at base level with melanoma somatic mutation hotspots. Our work provides proof of concept for the study of protein-DNA interactions at individual loci using light and sequencing, and reveals widespread and potent modulation of UV damage in regulatory regions. Proteins binding to DNA can locally alter DNA damage formation by UV light. Here, Elliott et al. generate high-resolution quantitative UV damage profiles for genomic regions of interest, revealing distinctive damage signatures for specific proteins and elevated UV damage at melanoma mutation hotspots.
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| 2. |
- Sengodan, Satheesh K., et al.
(författare)
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Mismatch repair protein MLH1 suppresses replicative stress in BRCA2-deficient breast tumors
- 2024
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Ingår i: JOURNAL OF CLINICAL INVESTIGATION. - 0021-9738 .- 1558-8238. ; 134:7
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Tidskriftsartikel (refereegranskat)abstract
- Loss of BRCA2 (breast cancer 2) is lethal for normal cells. Yet it remains poorly understood how, in BRCA2 mutation carriers, cells undergoing loss of heterozygosity overcome the lethality and undergo tissue -specific neoplastic transformation. Here, we identified mismatch repair gene mutL homolog 1 (MLH1) as a genetic interactor of BRCA2 whose overexpression supports the viability of Brca2-null cells. Mechanistically, we showed that MLH1 interacts with Flap endonuclease 1 (FEN1) and competes to process the RNA flaps of Okazaki fragments. Together, they restrained the DNA2 nuclease activity on the reversed forks of lagging strands, leading to replication fork (RF) stability in BRCA2-deficient cells. In these cells, MLH1 also attenuated R -loops, allowing the progression of stable RFs, which suppressed genomic instability and supported cell viability. We demonstrated the significance of their genetic interaction by the lethality of Brca2-mutant mice and inhibition of Brca2-deficient tumor growth in mice by Mlh1 loss. Furthermore, we described estrogen as inducing MLH1 expression through estrogen receptor alpha (ER alpha), which might explain why the majority of BRCA2 mutation carriers develop ER -positive breast cancer. Taken together, our findings reveal a role of MLH1 in relieving replicative stress and show how it may contribute to the establishment of BRCA2-deficient breast tumors.
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