Project description:In order to identify genes and pathways necessary to preserve genome integrity upon Myc over-expression, we conducted a large siRNA-based screen in isogenic lines. We discovered several genes that suppressed the Myc-induced DNA-damage response and that were essential for the cell survival upon Myc activation. We idntified CDK12, a cyclin dependent kinase involved in transcriptional control and genome stability. We uncovered a novel and unexpected role of CDK12 in controlling transcription at loci proximal to DNA damaged sites and dissected its upstream regulatory pathways and downstream effectors. Mechanistic studies and genome-wide mapping of replication dynamics and DSBs revealed how CDK12 is essential to suppress intrinsic transcription-replication conflicts, thus avoiding cytotoxic DNA damage in cancer cells. Overall, this study uncovers a novel role for CDK12 and a new liability of Myc-driven cancers, which could be exploited for therapeutic purposes.
Project description:In order to identify genes and pathways necessary to preserve genome integrity upon Myc over-expression, we conducted a large siRNA-based screen in isogenic lines. We discovered several genes that suppressed the Myc-induced DNA-damage response and that were essential for the cell survival upon Myc activation. We idntified CDK12, a cyclin dependent kinase involved in transcriptional control and genome stability. We uncovered a novel and unexpected role of CDK12 in controlling transcription at loci proximal to DNA damaged sites and dissected its upstream regulatory pathways and downstream effectors. Mechanistic studies and genome-wide mapping of replication dynamics and DSBs revealed how CDK12 is essential to suppress intrinsic transcription-replication conflicts, thus avoiding cytotoxic DNA damage in cancer cells. Overall, this study uncovers a novel role for CDK12 and a new liability of Myc-driven cancers, which could be exploited for therapeutic purposes.
Project description:In order to identify genes and pathways necessary to preserve genome integrity upon Myc over-expression, we conducted a large siRNA-based screen in isogenic lines. We discovered several genes that suppressed the Myc-induced DNA-damage response and that were essential for the cell survival upon Myc activation. We idntified CDK12, a cyclin dependent kinase involved in transcriptional control and genome stability. We uncovered a novel and unexpected role of CDK12 in controlling transcription at loci proximal to DNA damaged sites and dissected its upstream regulatory pathways and downstream effectors. Mechanistic studies and genome-wide mapping of replication dynamics and DSBs revealed how CDK12 is essential to suppress intrinsic transcription-replication conflicts, thus avoiding cytotoxic DNA damage in cancer cells. Overall, this study uncovers a novel role for CDK12 and a new liability of Myc-driven cancers, which could be exploited for therapeutic purposes.
Project description:In order to identify genes and pathways necessary to preserve genome integrity upon Myc over-expression, we conducted a large siRNA-based screen in isogenic lines. We discovered several genes that suppressed the Myc-induced DNA-damage response and that were essential for the cell survival upon Myc activation. We idntified CDK12, a cyclin dependent kinase involved in transcriptional control and genome stability. We uncovered a novel and unexpected role of CDK12 in controlling transcription at loci proximal to DNA damaged sites and dissected its upstream regulatory pathways and downstream effectors. Mechanistic studies and genome-wide mapping of replication dynamics and DSBs revealed how CDK12 is essential to suppress intrinsic transcription-replication conflicts, thus avoiding cytotoxic DNA damage in cancer cells. Overall, this study uncovers a novel role for CDK12 and a new liability of Myc-driven cancers, which could be exploited for therapeutic purposes.
Project description:In order to identify genes and pathways necessary to preserve genome integrity upon Myc over-expression, we conducted a large siRNA-based screen in isogenic lines. We discovered several genes that suppressed the Myc-induced DNA-damage response and that were essential for the cell survival upon Myc activation. We idntified CDK12, a cyclin dependent kinase involved in transcriptional control and genome stability. We uncovered a novel and unexpected role of CDK12 in controlling transcription at loci proximal to DNA damaged sites and dissected its upstream regulatory pathways and downstream effectors. Mechanistic studies and genome-wide mapping of replication dynamics and DSBs revealed how CDK12 is essential to suppress intrinsic transcription-replication conflicts, thus avoiding cytotoxic DNA damage in cancer cells. Overall, this study uncovers a novel role for CDK12 and a new liability of Myc-driven cancers, which could be exploited for therapeutic purposes.
Project description:Actively dividing cells perform robust and accurate DNA replication during fluctuating nutrient availability, yet factors that prevent disruption of replication remain largely unknown. Here we report that DksA, a nutrient-responsive transcription factor, ensures replication completion in Escherichia coli by removing transcription roadblocks. In the absence of DksA, replication is rapidly arrested upon amino acid starvation. This arrest requires active transcription and is alleviated by RNA polymerase mutants that compensate for DksA activity. This replication arrest occurs independently of exogenous DNA damage, yet it induces the DNA-damage response and recruits the main recombination protein RecA. This function of DksA is independent of its transcription initiation activity but requires its less-studied transcription elongation activity. Finally, GreA/B elongation factors also prevent replication arrest during nutrient stress. We conclude that transcription elongation factors alleviate fundamental conflicts between replication and transcription, thereby protecting replication fork progression and DNA integrity.
Project description:Effective spatio-temporal control of transcription and replication during S-phase is paramount to maintaining genomic integrity and cell survival. Dysregulation of these systems can lead to conflicts between the transcription and replication machinery, causing DNA damage and cell death. BRD4 allows efficient transcriptional elongation by stimulating phosphorylation of RNA polymerase II (RNAPII). We report that bromodomain and extra-terminal domain (BET) protein loss of function (LOF) causes RNAPII pausing on the chromatin and DNA damage affecting cells in S-phase. This persistent RNAPII-dependent pausing leads to an accumulation of RNA:DNA hybrids (R-loops) at sites of BRD4 occupancy, leading to transcription-replication conflicts (TRCs), DNA damage, and cell death. Finally, our data show that the BRD4 C-terminal domain, which interacts with P-TEFb, is required to prevent R-loop formation and DNA damage caused by BET protein LOF.