Display Settings:

Format

Send to:

Choose Destination
See comment in PubMed Commons below
Aging (Albany NY). 2009 Jan;1(1):28-37.

Genomic instability and DNA damage responses in progeria arising from defective maturation of prelamin A.

Author information

  • 1Department of Biochemistry & Molecular Biology, Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614-0581, USA.

Abstract

Progeria syndromes have in common a premature aging phenotype and increased genome instability. The susceptibility to DNA damage arises from a compromised repair system, either in the repair proteins themselves or in the DNA damage response pathways. The most severe progerias stem from mutations affecting lamin A production, a filamentous protein of the nuclear lamina. Hutchinson-Gilford progeria syndrome (HGPS) patients are heterozygous for aLMNA gene mutation while Restrictive Dermopathy (RD) individuals have a homozygous deficiency in the processing protease Zmpste24. These mutations generate the mutant lamin A proteins progerin and FC-lamina A, respectively, which cause nuclear deformations and chromatin perturbations. Genome instability is observed even though genome maintenance and repair genes appear normal. The unresolved question is what features of the DNA damage response pathways are deficient in HGPS and RD cells. Here we review and discuss recent findings which resolve some mechanistic details of how the accumulation of progerin/FC-lamin A proteins may disrupt DNA damage response pathways in HGPS and RD cells. As the mutant lamin proteins accumulate they sequester replication and repair factors, leading to stalled replication forks which collapse into DNA double-strand beaks (DSBs). In a reaction unique to HGPS and RD cells these accessible DSB termini bind Xeroderma pigmentosum group A (XPA) protein which excludes normal binding by DNA DSB repair proteins. The bound XPA also signals activation of ATM and ATR, arresting cell cycle progression, leading to arrested growth. In addition, the effective sequestration of XPA at these DSB damage sites makes HGPS and RD cells more sensitive to ultraviolet light and other mutagens normally repaired by the nucleotide excision repair pathway of which XPA is a necessary and specific component.

KEYWORDS:

DNA damage responses; DNA double strand breaks; DNA repair; Genome instability; Hutchinson-Gilford progeria syndrome; Lamin A; XPA; premature aging

PMID:
19851476
[PubMed - indexed for MEDLINE]
PMCID:
PMC2765059
Free PMC Article

Images from this publication.See all images (3)Free text

Figure 1.
Figure 2.
Figure 3.
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Impact Journals, LLC Icon for PubMed Central
    Loading ...
    Write to the Help Desk