Featured Research

from universities, journals, and other organizations

New Sequence Involved In DNA Replication Timing May Aid In Cancer Detection

Date:
September 28, 2004
Source:
American Society For Biochemistry And Molecular Biology
Summary:
Scientists have discovered a DNA sequence that is involved in controlling the timing of DNA replication. Because alterations in DNA replication timing are associated with cancer, this discovery may lead to improved methods for cancer detection.

Bethesda, MD - Scientists have discovered a DNA sequence that is involved in controlling the timing of DNA replication. Because alterations in DNA replication timing are associated with cancer, this discovery may lead to improved methods for cancer detection.

The research appears as the "Paper of the Week" in the October 1 issue of the Journal of Biological Chemistry, an American Society for Biochemistry and Molecular Biology journal.

Before a cell can divide, it must duplicate its DNA. Duplication, which occurs during the S phase of the cell cycle, is initiated at many replication origins in the DNA molecule. These replication origins fire at specific times throughout S phase, causing each segment of the genome to replicate at a precise time.

"S phase lasts about 8 hours in human cells and about 40 minutes in cells of the fission yeast, Schizosaccharomyces pombe," explained Joel A. Huberman of Roswell Park Cancer Institute. "In both cases, some portions of DNA molecules are nearly always duplicated early in S phase while other portions are nearly always duplicated late."

Until recently, very little was known about how cells control replication timing. Studies in budding yeast (Saccharomyces cerevisiae) have suggested that, by default, replication origins fire early in S phase, but they can be forced to fire later by flanking and internal DNA sequences. Now, Huberman and Chulee Yompakdee have discovered a stretch of DNA that verifies this hypothesis.

To study DNA replication timing, Huberman and Yompakdee used fission yeast as a model organism because of its small size, rapid cell cycle, and convenient genetics. "Human beings have 46 large chromosomes, while cells of the tiny fission yeast contain three much smaller chromosomes," noted Huberman. "Despite these differences, the process of DNA replication is very similar in humans and fission yeast."

The scientists found that the DNA surrounding many late-firing origins contains repeats of a 10-basepair sequence that is rich in the nucleic acid component, guanine. Yompakdee and Huberman named these repeats "Late Consensus Sequences" (LCS). They found that one copy of an LCS produced no detectable effect on replication timing, two copies produced a partial effect, and three copies caused replication to occur in late S phase. The researchers confirmed this finding by removing the LCSs from a late-replicating origin to convert it to an early-replicating origin.

"Interestingly," noted Huberman, "in many cancer cells, the normal order of DNA replication is altered: regions that should replicate late sometimes replicate early and vice versa." As a result, tests for DNA replication timing may eventually become a method for the early detection of cancer.

"Replication timing assays are one of many promising techniques that are currently being studied that may, in the future, allow much earlier cancer detection than is possible today," concluded Huberman.

###

The Journal of Biological Chemistry's Papers of the Week is an online feature which highlights the top one percent of papers received by the journal. Brief summaries of the papers and explanations of why they were selected for this honor can be accessed directly from the home page of the Journal of Biological Chemistry online at www.jbc.org.

The American Society for Biochemistry and Molecular Biology (ASBMB) is a nonprofit scientific and educational organization with over 11,000 members in the United States and internationally. Most members teach and conduct research at colleges and universities. Others conduct research in various government laboratories, nonprofit research institutions, and industry.

Founded in 1906, the Society is based in Bethesda, Maryland, on the campus of the Federation of American Societies for Experimental Biology. The Society's primary purpose is to advance the sciences of biochemistry and molecular biology through its publications, the Journal of Biological Chemistry, The Journal of Lipid Research, Molecular and Cellular Proteomics, and Biochemistry and Molecular Biology Education, and the holding of scientific meetings.

For more information about ASBMB, see the Society's website at http://www.asbmb.org.


Story Source:

The above story is based on materials provided by American Society For Biochemistry And Molecular Biology. Note: Materials may be edited for content and length.


Cite This Page:

American Society For Biochemistry And Molecular Biology. "New Sequence Involved In DNA Replication Timing May Aid In Cancer Detection." ScienceDaily. ScienceDaily, 28 September 2004. <www.sciencedaily.com/releases/2004/09/040928111519.htm>.
American Society For Biochemistry And Molecular Biology. (2004, September 28). New Sequence Involved In DNA Replication Timing May Aid In Cancer Detection. ScienceDaily. Retrieved July 25, 2014 from www.sciencedaily.com/releases/2004/09/040928111519.htm
American Society For Biochemistry And Molecular Biology. "New Sequence Involved In DNA Replication Timing May Aid In Cancer Detection." ScienceDaily. www.sciencedaily.com/releases/2004/09/040928111519.htm (accessed July 25, 2014).

Share This




More Health & Medicine News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

New Painkiller Designed To Discourage Abuse: Will It Work?

New Painkiller Designed To Discourage Abuse: Will It Work?

Newsy (July 24, 2014) The FDA approved Targiniq ER on Wednesday, a painkiller designed to keep users from abusing it. Like any new medication, however, it has doubters. Video provided by Newsy
Powered by NewsLook.com
Doctor At Forefront Of Fighting Ebola Outbreak Gets Ebola

Doctor At Forefront Of Fighting Ebola Outbreak Gets Ebola

Newsy (July 24, 2014) Sheik Umar Khan has treated many of the people infected in the Ebola outbreak, and now he's become one of them. Video provided by Newsy
Powered by NewsLook.com
Condemned Man's US Execution Takes Nearly Two Hours

Condemned Man's US Execution Takes Nearly Two Hours

AFP (July 24, 2014) America's death penalty debate raged Thursday after it took nearly two hours for Arizona to execute a prisoner who lost a Supreme Court battle challenging the experimental lethal drug cocktail. Duration: 00:55 Video provided by AFP
Powered by NewsLook.com
Can Watching TV Make You Feel Like A Failure?

Can Watching TV Make You Feel Like A Failure?

Newsy (July 24, 2014) A study by German researchers claims watching TV while you're stressed out can make you feel guilty and like a failure. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

    Health News

      Environment News

        Technology News



          Save/Print:
          Share:

          Free Subscriptions


          Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

          Get Social & Mobile


          Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

          Have Feedback?


          Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
          Mobile: iPhone Android Web
          Follow: Facebook Twitter Google+
          Subscribe: RSS Feeds Email Newsletters
          Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins