NAIST researchers show the molecular pathway through which plants cease cell division upon DNA damage
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 cell division in response to DNA damage 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 plants 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 cell cycle. 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 target genes 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 cells 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.
Title: Arabidopsis R1R2R3-Myb proteins are essential for inhibiting cell division in response to DNA damage
Authors: Poyu Chen, Hirotomo Takatsuka, Naoki Takahashi, Rie Kurata, Yoichiro Fukao, Kosuke Kobayashi, Masaki Ito & Masaaki Umeda*
Publication: Nature Communications. 8:635, 21 September 2017.
*Author for correspondence
Information about Prof. Umeda lab can be found at this website; http://bsw3.
NAIST was founded in 1991 as a Japanese national university consisting solely of graduate schools in three integrated areas: information science, biological sciences, and materials science. In the early 2018, NAIST will transform its current structure into the one graduate school system to further promote the mission of cultivating global leaders in science and technology who will actively respond to social demands. At present, about 1,000 students -22% from overseas- are supervised by roughly 200 NAIST faculty. With its cutting-edge facilities and a 5 to 1 student-to-faculty ratio, NAIST's world-leading research and education are a direct result of its rich, global environment and supportive infrastructure. NAIST has quickly established itself as a world-class research and education center where young scientists and technologists become tomorrow's global leaders. For more detail please visit: http://www.
Michiko Muraki | EurekAlert!
Researchers invent tiny, light-powered wires to modulate brain's electrical signals
21.02.2018 | University of Chicago
The “Holy Grail” of peptide chemistry: Making peptide active agents available orally
21.02.2018 | Technische Universität München
For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.
In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...
Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale
Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...
For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.
But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...
Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.
The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...
Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters
Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...
15.02.2018 | Event News
13.02.2018 | Event News
12.02.2018 | Event News
21.02.2018 | Life Sciences
21.02.2018 | Life Sciences
21.02.2018 | Materials Sciences