Abstract A11: RB localizes to DNA double strand breaks and promotes DNA end resection and homologous recombination through the recruitment of BRG1
Bibliographic record
Abstract
Abstract The retinoblastoma (RB) tumor suppressor is widely recognized as a master regulator of the transcriptional program that controls entry into the S phase of the cell cycle. Its loss, which is a hallmark of cancer, leads to uncontrolled cell proliferation. RB works by binding to members of the E2F family of transcription factors and recruiting chromatin modifiers and remodelers to the promoters of E2F target genes. Here we show that RB also localizes to DNA double strand breaks (DSBs) dependent on E2F1 and ATM kinase activity. RB promotes DNA end resection and DSB repair through homologous recombination (HR), and its loss results in genome instability. RB is necessary for the recruitment of the BRG1 ATPase to DSBs, which stimulates DNA end resection and HR. A knock-in mutation of the ATM phosphorylation site on E2F1 (S29A) prevents the interaction between E2F1 and TopBP1 and recruitment of RB, E2F1 and BRG1 to DSBs. This knock-in mutation also impairs DNA repair, increases genomic instability and renders mice hypersensitive to IR. Importantly, depletion of either RB or BRG1 in osteosarcoma and breast cancer cell lines results in sensitivity to DNA damaging agents, thus underscoring the importance of these factors in DNA repair. We uncover a novel, non-transcriptional function for RB in HR, which could contribute to genome instability associated with RB loss. Citation Format: Renier Vélez-Cruz, Swarnalatha Manickavinayaham, Anup K. Biswas, Regina W. Clary, David G. Johnson. RB localizes to DNA double strand breaks and promotes DNA end resection and homologous recombination through the recruitment of BRG1 [abstract]. In: Proceedings of the AACR Special Conference on DNA Repair: Tumor Development and Therapeutic Response; 2016 Nov 2-5; Montreal, QC, Canada. Philadelphia (PA): AACR; Mol Cancer Res 2017;15(4_Suppl):Abstract nr A11.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".