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An essential function for the ATR-Activation-Domain (AAD) of TopBP1 in mouse development and cellular senescence

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posted on 2023-06-08, 17:41 authored by Antony CarrAntony Carr, Zhao-Qi Wang, Min WooKee, Anja Krueger, Christopher Bruhn, Tang-Liang Li, Cong LiuCong Liu, Zhong-Wei Zhou
ATR activation is dependent on temporal and spatial interactions with partner proteins. In the budding yeast model, three proteins – Dpb11TopBP1, Ddc1Rad9 and Dna2 - all interact with and activate Mec1ATR. Each contains an ATR activation domain (ADD) that interacts directly with the Mec1ATR:Ddc2ATRIP complex. Any of the Dpb11TopBP1, Ddc1Rad9 or Dna2 ADDs is sufficient to activate Mec1ATR in vitro. All three can also independently activate Mec1ATR in vivo: the checkpoint is lost only when all three AADs are absent. In metazoans, only TopBP1 has been identified as a direct ATR activator. Depletion-replacement approaches suggest the TopBP1-AAD is both sufficient and necessary for ATR activation. The physiological function of the TopBP1 AAD is, however, unknown. We created a knock-in point mutation (W1147R) that ablates mouse TopBP1-AAD function. TopBP1-W1147R is early embryonic lethal. To analyse TopBP1-W1147R cellular function in vivo, we silenced the wild type TopBP1 allele in heterozygous MEFs. AAD inactivation impaired cell proliferation, promoted premature senescence and compromised Chk1 signalling following UV irradiation. We also show enforced TopBP1 dimerization promotes ATR-dependent Chk1 phosphorylation. Our data suggest that, unlike the yeast models, the TopBP1-AAD is the major activator of ATR, sustaining cell proliferation and embryonic development.

Funding

G0600233; MRC

G1100074; MRC

History

Publication status

  • Published

File Version

  • Published version

Journal

PLoS Genetics

ISSN

1553-7390

Publisher

Public Library of Science

Issue

8

Volume

9

Article number

e1003702

Department affiliated with

  • Sussex Centre for Genome Damage Stability Publications

Full text available

  • Yes

Peer reviewed?

  • Yes

Legacy Posted Date

2014-07-01

First Open Access (FOA) Date

2014-07-01

First Compliant Deposit (FCD) Date

2014-07-01

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