Lin_et_al,_2012.pdf (2.77 MB)
The Rad4TopBP1 ATR-Activation domain functions in G1/S phase in a chromatin-dependent manner
journal contribution
posted on 2023-06-08, 12:56 authored by Su-Jiun Lin, Christopher Paul Wardlaw, Takashi Morishita, Izumi Miyabe, Charly Chahwan, Thomas Caspari, Ulrike Schmidt, Antony CarrAntony Carr, Valerie GarciaDNA damage checkpoint activation can be subdivided in two steps: initial activation and signal amplification. The events distinguishing these two phases and their genetic determinants remain obscure. TopBP1, a mediator protein containing multiple BRCT domains, binds to and activates the ATR/ATRIP complex through its ATR-Activation Domain (AAD). We show that Schizosaccharomyces pombe Rad4TopBP1 AAD–defective strains are DNA damage sensitive during G1/S-phase, but not during G2. Using lacO-LacI tethering, we developed a DNA damage–independent assay for checkpoint activation that is Rad4TopBP1 AAD–dependent. In this assay, checkpoint activation requires histone H2A phosphorylation, the interaction between TopBP1 and the 9-1-1 complex, and is mediated by the phospho-binding activity of Crb253BP1. Consistent with a model where Rad4TopBP1 AAD–dependent checkpoint activation is ssDNA/RPA–independent and functions to amplify otherwise weak checkpoint signals, we demonstrate that the Rad4TopBP1 AAD is important for Chk1 phosphorylation when resection is limited in G2 by ablation of the resecting nuclease, Exo1. We also show that the Rad4TopBP1 AAD acts additively with a Rad9 AAD in G1/S phase but not G2. We propose that AAD–dependent Rad3ATR checkpoint amplification is particularly important when DNA resection is limiting. In S. pombe, this manifests in G1/S phase and relies on protein– chromatin interactions.
History
Publication status
- Published
File Version
- Published version
Journal
PLoS GeneticsISSN
1553-7390Publisher
Public Library of ScienceExternal DOI
Issue
6Volume
8Department affiliated with
- Sussex Centre for Genome Damage Stability Publications
Full text available
- Yes
Peer reviewed?
- Yes
Legacy Posted Date
2012-11-01First Open Access (FOA) Date
2012-11-01First Compliant Deposit (FCD) Date
2012-10-31Usage metrics
Categories
No categories selectedKeywords
Licence
Exports
RefWorks
BibTeX
Ref. manager
Endnote
DataCite
NLM
DC