JUN 06, 2018 5:48 PM PDT

New Role for Protein Complex Provides Insight Into Cancer Development

WRITTEN BY: Carmen Leitch

When our cells have to divide, all the genetic material they contain must be duplicated and then properly distributed to the two new cells so that each one gets 23 pairs of chromosomes. When that process goes awry in a developing organism, it can lead to serious developmental disorders; it is also associated with cancer. Now, researchers have revealed more about the molecular processes underlying chromosome segregation, which provides insight into why aggressive kidney tumors develop in some children. The work has been reported in The Journal of Cell Biology.

"When a cell makes a decision to divide it needs to make sure its DNA is equally segregated between both daughter cells," explained Tina Sing, who led this work in the lab of Professor Grant Brown at the Donnelly Centre and Department of Biochemistry at the University of Toronto. "The cells must first replicate their DNA and then they have to pull apart these two copies of the DNA so that each daughter cell receives one complete copy of the entire genome."

There are a number of diseases caused by the uneven distribution of chromosomes. People with an extra copy of chromosome 21 have Down syndrome. Women who lack the second copy of the X chromosome are sterile; a disorder called Turner syndrome. Chromosomal abnormalities are also often seen in cancer cells that can outgrow normal cells.

Related: A Pair of Genomes is Best

Sing, now a postdoctoral researcher at Berkeley, found that protein machinery used by the cell called the ‘risk complex’ for RSC (remodels the structure of chromatin), helps to split up the chromosomes evenly when a cell divides into daughter cells. RSC does this by helping to form a cellular structure called a centrosome, which acts to pull chromosomes apart. 

"We found that if cells lack RSC function then this causes abnormal DNA segregation and a spontaneous doubling of chromosome number in cells," said Sing.

In this research, Sing and Brown used a budding yeast model to show that when RSC is not working, the yeast cells behave as cancer would. The cells also had an unusually high number of chromosomes and had too many centrosomes. The yeast with mutated RSC had far more than the usual two centrosomes per cell, making the even separation of chromosomes extremely challenging.

RSC has been known as a molecule that helps control the expression of genes. This work ties other groups' findings on the protein complex in with a role for segregating chromosomes. It may indicate how one kind of childhood cancer forms.
 
When humans have certain mutations in their RSC gene, chromosome number can go up spontaneously. Such mutations have also been identified in very aggressive kidney cancer tumor cells. Yeast has helped show how these events might happen.

"It's always surprising to think about how fundamental processes in yeast also take place in humans," Sing noted. "We think that our study gives some insight into this observation in cancer cells and we think it's possible that this complex is also helping with chromosome segregation in human cells."

Sing started by looking at the known roles of RSC, but during that study, found that in cells where RSC wasn’t active, there were too many chromosomes. "The increase in chromosomes was more interesting than what we were looking for," she said. "I think the study is a good example of how sometimes when you set out to study a specific biological problem you can be surprised by the data that you find and sometimes just following your curiosity down a different path can lead to understanding another aspect of biology."


Sources: AAAS/Eurekalert! Via University of Toronto, Journal of Cell Biology 

About the Author
BS
Experienced research scientist and technical expert with authorships on over 30 peer-reviewed publications, traveler to over 70 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
NOV 28, 2022
Cell & Molecular Biology
From sample collection straight to RT-qPCR
NOV 28, 2022
From sample collection straight to RT-qPCR
Skip the nucleic acid purification step in your cancer detection workflow. Learn more about how Thermo Fisher Scientific ...
SEP 27, 2022
Neuroscience
How the Lactate Receptor is Related to Brain Injury in Newborns
SEP 27, 2022
How the Lactate Receptor is Related to Brain Injury in Newborns
Hypoxic-ischemic brain injury, which occurs when the brain's supply of oxygen and blood is blocked for a period of time, ...
OCT 06, 2022
Microbiology
A Microbial Predator Can Wreak Havoc in the Desert
OCT 06, 2022
A Microbial Predator Can Wreak Havoc in the Desert
The microorganisms of the world are in constant conflict, battling for resources and space in a microbial arms race. Som ...
OCT 21, 2022
Drug Discovery & Development
Gel-encased Radioactive Iodine Eliminates Pancreatic Cancer in Mice
OCT 21, 2022
Gel-encased Radioactive Iodine Eliminates Pancreatic Cancer in Mice
Researchers have developed a radioactive gel that eliminated pancreatic tumors in 80% of mice. The corresponding study w ...
NOV 04, 2022
Health & Medicine
Cannabis Users and Liver Transplants
NOV 04, 2022
Cannabis Users and Liver Transplants
Are cannabis consumers eligible for liver transplants? Here's the details
NOV 25, 2022
Neuroscience
Persistent Asthma Clogs Arteries to the Brain, Increases Cardiovascular Risk
NOV 25, 2022
Persistent Asthma Clogs Arteries to the Brain, Increases Cardiovascular Risk
Persistent asthma is linked to higher levels of inflammation and plaque in the arteries that deliver blood to the brain, ...
Loading Comments...