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Gene switch may repair DNA and prevent cancer

Date:
February 12, 2016
Source:
Institute for Integrated Cell-Material Sciences, Kyoto University
Summary:
New discoveries are bringing scientists closer to understanding how DNA repairs itself with a chemical modification which, when absent, can lead to tumor formation.
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FULL STORY

Damaged DNA strands are shown (Artist representation).
Credit: Bruce Rolff (123rf)

A team of scientists in Japan has found that a DNA modification called 5hmC -- thought to be involved in turning genes on and off -- localizes at sites of DNA damage and repair. They also found that a family of recently discovered enzymes, called TETs for short, is important in maintaining 5hmC's reparative role.

To turn genes on or off, a methyl group can be added to or removed from DNA. During the removal of this chemical tag, called demethylation, the methyl group is converted to 5hmC as an intermediate step. The TET enzymes are thought to be critical to the demethylation process. Recent research has shown that 5hmC is associated with an "opening up" of nearby chromatin, the tightly packaged assembly of proteins and DNA in the cell nucleus.

The team reveals in the journal Cell Reports that 5hmC localizes near breaks in DNA that develop naturally or that are caused by DNA-damaging drugs or irradiation. They also found that inhibiting TET enzymes in cells resulted in a lack of 5hmC, followed by errors in chromosome separation. This suggests that TET enzymes are important for the production of 5hmC at DNA damage sites and that both play critical roles in responding to DNA damage.

The research raises the possibility that 5hmC helps to keep chromatin "open" so it can be more accessible to other DNA damage response proteins. 5hmC could be used as a marker for DNA damage, say the researchers.

"Our results imply that loss of TET enzymes and 5hmC depletion could contribute significantly to genome instability and inaccurate chromosome segregation, perhaps explaining the correlation of low 5hmC levels with cancer," say the researchers.


Story Source:

The above post is reprinted from materials provided by Institute for Integrated Cell-Material Sciences, Kyoto University. Note: Materials may be edited for content and length.


Journal Reference:

  1. Georgia Rose Kafer, Xuan Li, Takuro Horii, Isao Suetake, Shoji Tajima, Izuho Hatada, Peter Mark Carlton. 5-Hydroxymethylcytosine Marks Sites of DNA Damage and Promotes Genome Stability. Cell Reports, 2016; DOI: 10.1016/j.celrep.2016.01.035

Cite This Page:

Institute for Integrated Cell-Material Sciences, Kyoto University. "Gene switch may repair DNA and prevent cancer." ScienceDaily. ScienceDaily, 12 February 2016. <www.sciencedaily.com/releases/2016/02/160212102340.htm>.
Institute for Integrated Cell-Material Sciences, Kyoto University. (2016, February 12). Gene switch may repair DNA and prevent cancer. ScienceDaily. Retrieved July 25, 2016 from www.sciencedaily.com/releases/2016/02/160212102340.htm
Institute for Integrated Cell-Material Sciences, Kyoto University. "Gene switch may repair DNA and prevent cancer." ScienceDaily. www.sciencedaily.com/releases/2016/02/160212102340.htm (accessed July 25, 2016).

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