Science News
from research organizations

Detector of DNA damage: Structure of a repair factor revealed

Date:
June 19, 2012
Source:
Ludwig-Maximilians-Universität München
Summary:
Double-stranded breaks in cellular DNA can trigger tumorigenesis. Researchers have now determined the structure of a protein involved in the repair and signaling of DNA double-strand breaks. The work throws new light on the origins of neurodegenerative diseases and certain tumor types.
Share:
       
FULL STORY

Double-stranded breaks in cellular DNA can trigger tumorigenesis. LMU researchers have now determined the structure of a protein involved in the repair and signaling of DNA double-strand breaks. The work throws new light on the origins of neurodegenerative diseases and certain tumor types.

Agents such as radiation or environmental toxins can cause double-stranded breaks in genomic DNA, which facilitate the development of tumors or the neurodegenerative disorders ataxia telangiectasia (AT) and AT-like disease (ATLD). Hence efficient repair mechanisms are essential for cell survival and function. The so-called MRN complex is an important component of one such system, and its structure has just been elucidated by a team led by Professor Karl-Peter Hopfner of LMU's Gene Center.

Malignant mutations

The MRN complex consists of the nuclease Mre11, the ATPase Rad50 and the protein Nbs1. Nbs1 is responsible for recruiting the protein ATM, which plays a central role in early stages of the cellular response to DNA damage, to the site of damage. "How the MRN complex actually recognizes double-stranded breaks is still not clear," says Hopfner. He and his colleagues therefore set out to clarify the issue by analyzing the structures of mutant, functionally defective versions of the complex.

"We found that pairs of Mre11 molecules form a flexible dimer, which is stabilized by Nbs1." Mutations in different subunits of the complex are associated with distinct syndromes, marked by a predisposition to certain cancers, sensitivity to radiation or neurodegeneration. Hopfner's results help to explain these differences. For instance, the mutation linked to ATLD lies within the zone of contact between Mre11 and Nbs1, and may inhibit activation of ATM by weakening their interaction. 


Story Source:

The above post is reprinted from materials provided by Ludwig-Maximilians-Universität München. Note: Materials may be edited for content and length.


Journal Reference:

  1. Christian B Schiller, Katja Lammens, Ilaria Guerini, Britta Coordes, Heidi Feldmann, Florian Schlauderer, Carolin Möckel, Alexandra Schele, Katja Strässer, Stephen P Jackson, Karl-Peter Hopfner. Structure of Mre11–Nbs1 complex yields insights into ataxia-telangiectasia–like disease mutations and DNA damage signaling. Nature Structural & Molecular Biology, 2012; DOI: 10.1038/nsmb.2323

Cite This Page:

Ludwig-Maximilians-Universität München. "Detector of DNA damage: Structure of a repair factor revealed." ScienceDaily. ScienceDaily, 19 June 2012. <www.sciencedaily.com/releases/2012/06/120619112857.htm>.
Ludwig-Maximilians-Universität München. (2012, June 19). Detector of DNA damage: Structure of a repair factor revealed. ScienceDaily. Retrieved September 2, 2015 from www.sciencedaily.com/releases/2012/06/120619112857.htm
Ludwig-Maximilians-Universität München. "Detector of DNA damage: Structure of a repair factor revealed." ScienceDaily. www.sciencedaily.com/releases/2012/06/120619112857.htm (accessed September 2, 2015).

Share This Page: