Related Experiment Video
Updated: Jun 8, 2026
11:06
Identifying DNA Mutations in Purified Hematopoietic Stem/Progenitor Cells
Published on: February 24, 2014
BLM Deficiency Is Not Associated with Sensitivity to Hydroxyurea-Induced Replication Stress.
Kenza Lahkim Bennani-Belhaj1, Géraldine Buhagiar-Labarchède, Nada Jmari
1Institut Curie, Centre de Recherche, Centre Universitaire, Bât. 110, 91405 Orsay, France.
Journal of Nucleic Acids
|October 12, 2010
Summary
Bloom's syndrome (BS) cells, despite endogenous replication stress, show no sensitivity to hydroxyurea (HU). This suggests BS cells adapt to replication stress, leading to insensitivity to external replication inhibitors.
Area of Science:
- Genetics
- Molecular Biology
- Cancer Research
Background:
- Bloom's syndrome (BS) is linked to chromosomal instability and early-onset cancer.
- BS cells exhibit slow replication fork velocity and inherent replication stress.
- Conflicting data exists on BS cell response to hydroxyurea (HU)-induced replication stress.
Purpose of the Study:
- To clarify the response of Bloom's syndrome cells to hydroxyurea (HU)-induced replication stress.
- To investigate the impact of BLM deficiency on cellular survival and genomic integrity under replication stress.
Main Methods:
- Utilized two distinct cellular models of Bloom's syndrome.
- Assessed clonogenic survival, double-strand break (DSB) generation, and sister chromatid exchange (SCE) induction after HU treatment.
Main Results:
- BLM deficiency did not correlate with sensitivity to HU.
- No significant differences in clonogenic survival, DSB generation, or SCE induction were observed between BS and control cells upon HU exposure.
Conclusions:
- Bloom's syndrome cells are not sensitive to HU-induced replication stress.
- Surviving BLM-deficient cells may possess mechanisms to cope with endogenous replication stress, conferring resistance to external agents like HU.
Related Concept Videos
01:02The DNA Replication Fork
An organism’s genome needs to be duplicated in an efficient and error-free manner for its growth and survival. The replication fork is a Y-shaped active region where two strands of DNA are separated and replicated continuously. The coupling of DNA unzipping and complementary strand synthesis is a characteristic feature of a replication fork. Organisms with small circular DNA, such as E. coli, often have a single origin of replication; therefore, they have only two replication forks, one in...
02:37Restarting Stalled Replication Forks
DNA replication is initiated at sites containing predefined DNA sequences known as origins of replication. DNA is unwound at these sites by the minichromosome maintenance (MCM) helicase and other factors such as Cdc45 and the associated GINS complex.The unwound single strands are protected by replication protein A (RPA) until DNA polymerase starts synthesizing DNA at the 5’ end of the strand in the same direction as the replication fork. To prevent the replication fork from falling apart, a...
02:36DNA Damage can Stall the Cell Cycle
In response to DNA damage, cells can pause the cell cycle to assess and repair the breaks. However, the cell must check the DNA at certain critical stages during the cell cycle. If the cell cycle pauses before DNA replication, the cells will contain twice the amount of DNA. On the other hand, if cells arrest after DNA replication but before mitosis, they will contain four times the normal amount of DNA. With a host of specialized proteins at their disposal,cells must use the right protein at...
01:20Mismatch Repair
Organisms are capable of detecting and fixing nucleotide mismatches that occur during DNA replication. This sophisticated process requires identifying the new strand and replacing the erroneous bases with correct nucleotides. Mismatch repair is coordinated by many proteins in both prokaryotes and eukaryotes.
The Mutator Protein Family Plays a Key Role in DNA Mismatch Repair
The human genome has more than 3 billion base pairs of DNA per cell. Prior to cell division, that vast amount of genetic...
The Mutator Protein Family Plays a Key Role in DNA Mismatch Repair
The human genome has more than 3 billion base pairs of DNA per cell. Prior to cell division, that vast amount of genetic...
01:28Inhibitors of Bacterial DNA Synthesis
Bacterial pathogens depend on precise and efficient DNA replication to sustain infection. Two type II topoisomerases—DNA gyrase and topoisomerase IV—are critical to this process, as they resolve DNA supercoiling and unlink chromosomes during replication. Fluoroquinolones, synthetic derivatives of quinolones, exploit this mechanism by stabilizing the transient DNA–enzyme cleavage complex, preventing strand religation, and causing lethal double-strand breaks. These antibiotics are selectively...
02:10Translesion DNA Polymerases
Translesion (TLS) polymerases rescue stalled DNA polymerases at sites of damaged bases by replacing the replicative polymerase and installing a nucleotide across the damaged site. Doing so, TLS allows additional time for the cell to repair the damage before resuming regular DNA replication.
TLS polymerases are found in all three domains of life - archaea, bacteria, and eukaryotes. Of the different classes of TLS polymerases, members of the Y family are fitted with specialized structures that...
TLS polymerases are found in all three domains of life - archaea, bacteria, and eukaryotes. Of the different classes of TLS polymerases, members of the Y family are fitted with specialized structures that...