Telomeres resemble DNA fragile sites(omeres resembled common fragile sites su...)

Date:7/10/2009

omeres resembled common fragile sites, suggesting that TRF1 protects telomeres from becoming fragile. Instead of a continuous string of DNA, the telomeres were broken into fragments of twos and threes. To see if the replication fork stalls at telomeres, de Lange and Sfeir joined forces with Carl L. Schildkraut, a researcher at Albert Einstein College of Medicine in New York City. Using a technique called SMARD, the researchers observed the dynamics of replication across individual DNA molecules the first time this technique has been used to study telomeres. In the absence of TRF1, the fork often stalled for a considerable amount of time.

The only other known replication problem posed by telomeres was solved in 1985 when it was shown that the enzyme telomerase elongates telomeres, which shorten during every cell division. The second problem posed by telomeres, the so-called end-protection problem, was solved by de Lange and her colleagues when they found that shelterin protects the ends of linear chromosomes, which look like damaged DNA, from unnecessary repair. Working with TRF1, the very first shelterin protein ever to be identified, de Lange and Sfeir have not only unveiled a completely unanticipated replication problem at telomeres, they have also shown how it is solved.

The research lays new groundwork for the study of common fragile sites throughout the genome, explains de Lange. "Fragile sites have always been hard to study because no specific DNA sequence preceeds or follows them," she says. "In constrast, telomeres represent fragile sites with a known sequence, which may help us understand how common fragile sites break throughout the genome and why."

'/>"/>

Contact: Thania Benios tbenios@rockefeller.edu 212-327-7146 Rockefeller University Source:Eurekalert

0 GOOD

Page: 1 2
Related biology news :

1. Satellite imagery shows fragile Wilkins Ice Shelf destabilized
2. Promising new drug being evaluated as possible treatment option for fragile X syndrome
3. M.I.N.D. Institute researchers call for fragile X testing throughout the lifespan
4. UCR researchers propose minocycline as a promising drug for patients with Fragile X syndrome
5. Experts meet on need for new rules to govern worlds fragile polar regions
6. Researcher helping to pioneer medical therapy for Fragile X Syndrome presents latest findings
7. Effective ADHD treatment found for children with fragile X syndrome
8. Deep into the machinery of adult fragile X
9. Scientists link fragile X tremor/ataxia syndrome to binding protein in RNA
10. Study finds role for parasites in evolution of sex
11. Immune genes adapt to parasites