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Updated: Jul 13, 2026
Associated Chromosome Trap for Identifying Long-range DNA Interactions
Published on: April 23, 2011
Probing ATR activation with model DNA templates
1Stanford University, Department of Chemical and Systems Biology, Stanford, California 94305-5441, USA. cimprich@stanford.edu
Abstract:
The ATR kinase is a critical upstream component of a checkpoint pathway that responds to many forms of damaged and incompletely replicated DNA. Cellular processes such as DNA replication and repair are thought to convert these DNA lesions into a common DNA intermediate that activates this signaling pathway. Indeed, numerous studies have shown that two DNA structures formed during these processes--single-stranded DNA (ssDNA) and junctions between double-stranded DNA (dsDNA) and ssDNA--are important components of the ATR-activating structure. However, an unanswered question is whether primed ssDNA is sufficient for activation of the ATR response. We recently demonstrated that primed ssDNA is sufficient to induce a bona fide checkpoint response in Xenopus egg extracts. This is the first well-defined DNA structure capable of eliciting ATR activation. Using this structure, we examined the contribution of ds/ssDNA junctions and ssDNA to checkpoint activation. Our results indicate the context in which the checkpoint-activating structure is generated may contribute significantly to its signaling properties. Here we discuss the implications of our findings, in the context of other recent work in the field, on our understanding of checkpoint signaling.
Insights
Primed single-stranded DNA (ssDNA) can activate the ATR kinase, a key component of DNA damage checkpoints. This finding clarifies the DNA structures necessary for initiating cellular responses to DNA replication stress.
Area of Science:
- Cellular biology
- Molecular genetics
- Biochemistry
Background:
- The ATR kinase pathway is crucial for responding to DNA damage and replication stress.
- DNA replication and repair processes generate DNA structures that activate ATR signaling.
- Single-stranded DNA (ssDNA) and double-stranded/single-stranded DNA (ds/ssDNA) junctions are known components of ATR-activating structures.
Purpose of the Study:
- To determine if primed ssDNA alone is sufficient to activate the ATR response.
- To investigate the roles of ds/ssDNA junctions and ssDNA in checkpoint activation using a defined DNA structure.
Main Methods:
- Utilized Xenopus egg extracts to study ATR activation.
- Employed a well-defined primed ssDNA structure to elicit checkpoint responses.
- Examined the contribution of different DNA structures to checkpoint signaling.
Main Results:
- Demonstrated that primed ssDNA is sufficient to induce a bona fide checkpoint response in Xenopus egg extracts.
- Identified primed ssDNA as the first well-defined DNA structure capable of eliciting ATR activation.
- Showed that the context of checkpoint-activating structure generation influences signaling properties.
Conclusions:
- Primed ssDNA is sufficient for ATR activation, establishing a minimal requirement for checkpoint signaling.
- The cellular context and the specific DNA structures involved in ATR activation are critical for signaling outcomes.
- Findings advance the understanding of DNA damage and replication checkpoint mechanisms.
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