Accession Number:

ADB264750

Title:

Mechanisms and Components of the DNA Damage Checkpoint

Descriptive Note:

Annual rept. 1 Sep 1999-31 Aug 2000

Corporate Author:

YALE UNIV NEW HAVEN CT

Personal Author(s):

Report Date:

2000-09-01

Pagination or Media Count:

17.0

Abstract:

The DNA damage checkpoint DDC, controls the cellular response to DNA damage. Loss of function of components of the mammalian DDC, such as ATM, hChk2, p53, and BRCA1, correlates with increased cancer risk. Eukaryotic DDC mechanisms are conserved in Saccharomyces cerevisiae, ATM-family kinase Mec 1 is required for the DDC, as are Rad53 and Rad9. Rad53 is the founding member of a kinase family implicated in DDCs, including mammalian homolog hChk2. Rad9 shares homology with the BRCA1 C- terminus. S. cerevisiae thus provides a powerful genetic system in which to study the conserved DDC mechanisms. The Mec1-dependent phosphorylation of Rad53 correlates with the propagation of the DDC signal. Mec1 is also required for the DDC-dependent phosphorylation of Rad9, leading to the binding of Kad53 to phospho-Rad9 via the second FHA domain within Rad53. A goal of this work is to characterize physical and catalytic interactions between Mec1, Rad53, and Rad9. As reported herein, we identified sites within Rad9 required for both the phosphorylation of Rad9 and for interaction with Rad53. These sites are putative Mec1 substrates. We cloned, tagged, and expressed Mec1, and demonstrated that it phosphorylates Rad9 in vitro. Further, in vitro Rad53 FHA2 binds this Rad9 phosphopeptide.

Subject Categories:

  • Anatomy and Physiology
  • Medicine and Medical Research
  • Microbiology

Distribution Statement:

APPROVED FOR PUBLIC RELEASE