Xenopus Cdc7 executes its essential function early in S phase and is counteracted by checkpoint-regulated protein phosphatase 1
Poh, Wei Theng ; Chadha, Gaganmeet Singh ; Gillespie, Peter J. ; Kaldis, Philipp LU
and Blow, J. Julian
(2014)
In Open biology
4(1).
- Abstract
The initiation of DNA replication requires two protein kinases: cyclin-dependent kinase (Cdk) and Cdc7. Although S phase Cdk activity has been intensively studied, relatively little is known about how Cdc7 regulates progression through S phase. We have useda Cdc7 inhibitor, PHA-767491, todissect the role of Cdc7 in Xenopus egg extracts. We show that hyperphosphorylation of mini-chromosome maintenance (MCM) proteins by Cdc7 is required for the initiation, but not for the elongation, of replication forks. Unlike Cdks, we demonstrate that Cdc7 executes its essential functions by phosphorylating MCM proteins at virtually all replication origins early in S phase and is not limiting for progression through the Xenopus replication timing... (More)
The initiation of DNA replication requires two protein kinases: cyclin-dependent kinase (Cdk) and Cdc7. Although S phase Cdk activity has been intensively studied, relatively little is known about how Cdc7 regulates progression through S phase. We have useda Cdc7 inhibitor, PHA-767491, todissect the role of Cdc7 in Xenopus egg extracts. We show that hyperphosphorylation of mini-chromosome maintenance (MCM) proteins by Cdc7 is required for the initiation, but not for the elongation, of replication forks. Unlike Cdks, we demonstrate that Cdc7 executes its essential functions by phosphorylating MCM proteins at virtually all replication origins early in S phase and is not limiting for progression through the Xenopus replication timing programme. We demonstrate that protein phos-phatase 1 (PP1) is recruited to chromatin and rapidly reverses Cdc7-mediated MCM hyperphosphorylation. Checkpoint kinases induced by DNA damage or replication inhibition promote the association of PP1 with chromatin and increase the rate of MCM dephosphorylation, thereby counteracting the previously completed Cdc7 functions and inhibiting replication initiation. This novel mechanism for regulating Cdc7 function provides an explanation for previous contradictory results concerning the control of Cdc7 by checkpoint kinases and has implications for the use of Cdc7 inhibitors as anti-cancer agents.
(Less)
- author
- Poh, Wei Theng
; Chadha, Gaganmeet Singh
; Gillespie, Peter J.
; Kaldis, Philipp
LU
and Blow, J. Julian
- publishing date
- 2014-01-08
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Cdc7, DNA replication, PHA-767491, PP1, Xenopus
- in
- Open biology
- volume
- 4
- issue
- 1
- article number
- 130138
- publisher
- Royal Society Publishing
- external identifiers
-
- pmid:24403013
- scopus:84893920915
- ISSN
- 2046-2441
- DOI
- 10.1098/rsob.130138
- language
- English
- LU publication?
- no
- id
- 2d6ca22b-942f-4095-876a-c8b20a36ec54
- date added to LUP
- 2019-09-18 13:55:14
- date last changed
- 2024-01-01 20:34:28
@article{2d6ca22b-942f-4095-876a-c8b20a36ec54,
abstract = {{<p>The initiation of DNA replication requires two protein kinases: cyclin-dependent kinase (Cdk) and Cdc7. Although S phase Cdk activity has been intensively studied, relatively little is known about how Cdc7 regulates progression through S phase. We have useda Cdc7 inhibitor, PHA-767491, todissect the role of Cdc7 in Xenopus egg extracts. We show that hyperphosphorylation of mini-chromosome maintenance (MCM) proteins by Cdc7 is required for the initiation, but not for the elongation, of replication forks. Unlike Cdks, we demonstrate that Cdc7 executes its essential functions by phosphorylating MCM proteins at virtually all replication origins early in S phase and is not limiting for progression through the Xenopus replication timing programme. We demonstrate that protein phos-phatase 1 (PP1) is recruited to chromatin and rapidly reverses Cdc7-mediated MCM hyperphosphorylation. Checkpoint kinases induced by DNA damage or replication inhibition promote the association of PP1 with chromatin and increase the rate of MCM dephosphorylation, thereby counteracting the previously completed Cdc7 functions and inhibiting replication initiation. This novel mechanism for regulating Cdc7 function provides an explanation for previous contradictory results concerning the control of Cdc7 by checkpoint kinases and has implications for the use of Cdc7 inhibitors as anti-cancer agents.</p>}},
author = {{Poh, Wei Theng and Chadha, Gaganmeet Singh and Gillespie, Peter J. and Kaldis, Philipp and Blow, J. Julian}},
issn = {{2046-2441}},
keywords = {{Cdc7; DNA replication; PHA-767491; PP1; Xenopus}},
language = {{eng}},
month = {{01}},
number = {{1}},
publisher = {{Royal Society Publishing}},
series = {{Open biology}},
title = {{Xenopus Cdc7 executes its essential function early in S phase and is counteracted by checkpoint-regulated protein phosphatase 1}},
url = {{http://dx.doi.org/10.1098/rsob.130138}},
doi = {{10.1098/rsob.130138}},
volume = {{4}},
year = {{2014}},
}