Plant cells survive but stop dividing upon DNA damage

October 6, 2017, Nara Institute of Science and Technology
Green spots indicate a transcription factor that accumulates and inhibits cell division upon DNA damage. Researchers found an indispensable role of the transcription factor in arresting plant growth under stressful conditions. Credit: Masaaki Umeda

The cell cycle is the system through which a cell grows and divides. It is also how a cell passes its DNA to its progeny and is why the cell cycle ceases if the DNA is damaged, as otherwise it risks passing this damage to daughter cells. Scientists at the Nara Institute of Science and Technology (NAIST) have reported a new molecular mechanism that explains how this cessation occurs. The study, which can be read in Nature Communications, shows the transcription factor family MYB3R prevents progression to the division stage (M phase) of the cell cycle in Arabidopsis, a small flowering plant that is a member of the mustard family.

"Inhibition of in response to DNA enables cells to maintain genome integrity. The inhibition is regulated by different molecules in animals and plants," explains NAIST Professor Masaaki Umeda, who studies the role of stem cells in plant growth.

MYB3R can be divided into groups of transcription activators (Act-MYB) and transcription repressors (Rep-MYB). Plants grow through their root tip and shoot apex, but not upon DNA damage. In the study, Prof. Umeda and his colleagues found termination of the growth was accompanied by an accumulation of Rep-MYB proteins in these regions and that absent this accumulation, the would show signs of growing leaves and flowers.

To understand how this accumulation occurs in response to DNA damage, the scientists considered the role of CDK, or cyclin-dependent kinases. CDKs are crucial for the regulation of the . DNA damage suppresses CDK activity, which prevents progression to M phase. Prof. Umeda found that inhibiting CDKs even with the absence of DNA damage would cause the Rep-MYB3R accumulation seen with DNA damage and stall the cell cycle before the M phase transition. "We found that CDK activity is required for Rep-MYB degradation under normal conditions. The degradation is suppressed due to DNA damage," he said.

The study further found that the accumulated Rep-MYB proteins responsible for transitioning the cell to M phase. "Rep-MYB has a number of G2/M-specific target genes. We found that they stop plant growth by targeting only a specific set of these genes," notes Prof. Umeda.

Why only a specific set and not all its target genes is unclear, though Prof. Umeda suggests that this finding could be evidence that a cofactor that interacts with Rep-MYB may determine the selectivity. Prof. Umeda says that the study provides a new paradigm for how plant cell division ceases upon DNA damage, thus preventing damaged from accumulating under stressful conditions. "Without DNA damage, CDK prevents Rep-MYB from activating, which allows the cell cycle to progress to cell division. DNA damage inhibits CDK activity, freeing Rep-MYB and stopping the cell division," he says.

Explore further: Researchers establish key mechanism controlling cell division

More information: Poyu Chen et al, Arabidopsis R1R2R3-Myb proteins are essential for inhibiting cell division in response to DNA damage, Nature Communications (2017). DOI: 10.1038/s41467-017-00676-4

Related Stories

Plants sacrifice 'daughters' to survive chilly weather

June 23, 2017

Plants adopt different strategies to survive the changing temperatures of their natural environments. This is most evident in temperate regions where forest trees shed their leaves to conserve energy during the cold season. ...

How DNA damage turns immune cells against cancer

July 31, 2017

Cancer is essentially a disease of the cell replication cycle. The goal of treating the disease is to permanently kill off the cells that replicate with abandon without any molecular brakes. Chemotherapy and radiation cause ...

The fork in the road to DNA repair

July 12, 2017

Japanese researchers from Osaka University have uncovered a way in which our cells regulate the repair of broken DNA. Their results, published in the journal Cell Reports show a common molecule regulates multiple repair mechanisms ...

Controls of specialization unraveled

November 4, 2015

Two phases of the cell cycle of human embryonic stem cells have been shown, for the first time, to actively employ pathways that maintain pluripotency—the potential to develop into almost any type of cell in the body.

Recommended for you

Scientists crack genetic code of cane toad

September 19, 2018

A group of scientists from UNSW Sydney, the University of Sydney, Deakin University, Portugal and Brazil have unlocked the DNA of the cane toad, a poisonous amphibian that is a threat to many native Australian species. The ...

Scientists examine variations in a cell's protein factory

September 19, 2018

You can think of a cell in your body like a miniature factory, creating a final product called proteins, which carry out various tasks and functions. In this cellular factory, genes control the series of sequential steps ...

Why some animals still have a penis bone

September 19, 2018

A team of researchers affiliated with several institutions in the U.K. has found a possible explanation for why some animals still have a penis bone—"prolonged intromission." In their paper published in Proceedings of the ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.