The chopping up of a cell's DNA occurs in response to damage, for example, from ultraviolet light, and appears to be a means of killing the cell before it can become dysfunctional or cancerous. The proteins are produced by two cellular processes, both of which must be set in motion before the proteins can gang up on the DNA molecule and seal the cell's fate. The researchers describe their discovery in the July 7 issue of Archives of Internal Medicine.
The self-killing of cells is termed apoptosis, and its purposes include not only culling damaged cells but shaping an embryo by getting rid of webbing tissue between fingers and toes. By contributing to the understanding of how apoptosis works, the researchers, led by Zigang Dong of the university's Hormel Institute in Austin, Minn., hope someday to see the process used to kill cancer cells or other unwanted tissue.
The "bodyguard" protein belongs to a class of proteins called histones, which act like spools for the "thread" of DNA molecules. Rather than float in the cell nucleus like an overlong piece of spaghetti, the DNA molecule loops around regularly spaced histones, which not only support the DNA but play various roles in managing its functions.
"In the past, people thought histones were just for packaging DNA," said Dong, who studied a histone named H2AX. "People believe H2AX plays a role in DNA repair. But we find that if DNA can't be repaired, the cell undergoes apoptosis. The histone H2AX is probably important for both apoptosis and DNA repair."
Dong and his colleagues were led to the discovery by their previous work on the biochemistry of skin cancer. They had previously found that various forms of an enzyme known as JNK played a role in the development of the cancer. Working with cells from the skin of mice, they have now discovered that after they expose cells to damaging amounts of ultraviolet light, a form of JNK initiates both of the cellular processes that culminate in DNA destruction.
In one process, JNK starts a chain reaction that leads to the activation of an enzyme that chops up DNA. In the other process, JNK activates the histone H2AX. The activated enzyme and the activated histone work together to make mincemeat of the DNA. Dong and his colleagues are the first to show that activation of H2AX is necessary for apoptosis to occur by means of the DNA-chopping enzyme. The work was supported by the Hormel Foundation and the National Institutes of Health.
Mark Cassutt | EurekAlert!
Mass spectrometry sheds new light on thallium poisoning cold case
14.12.2018 | University of Maryland
Protein involved in nematode stress response identified
14.12.2018 | University of Illinois College of Agricultural, Consumer and Environmental Sciences
The more objects we make "smart," from watches to entire buildings, the greater the need for these devices to store and retrieve massive amounts of data quickly without consuming too much power.
Millions of new memory cells could be part of a computer chip and provide that speed and energy savings, thanks to the discovery of a previously unobserved...
What if, instead of turning up the thermostat, you could warm up with high-tech, flexible patches sewn into your clothes - while significantly reducing your...
A widely used diabetes medication combined with an antihypertensive drug specifically inhibits tumor growth – this was discovered by researchers from the University of Basel’s Biozentrum two years ago. In a follow-up study, recently published in “Cell Reports”, the scientists report that this drug cocktail induces cancer cell death by switching off their energy supply.
The widely used anti-diabetes drug metformin not only reduces blood sugar but also has an anti-cancer effect. However, the metformin dose commonly used in the...
A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.
Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...
Over the last decade, there has been much excitement about the discovery, recognised by the Nobel Prize in Physics only two years ago, that there are two types...
12.12.2018 | Event News
10.12.2018 | Event News
06.12.2018 | Event News
14.12.2018 | Power and Electrical Engineering
14.12.2018 | Physics and Astronomy
14.12.2018 | Physics and Astronomy