Location Is Key in Enzyme's Role in Cell Cycle Regulation

Newswise — Researchers at SUNY Upstate Medical University have a new understanding of how cell cycle regulation is affected by RNA degrading enzymes. In this latest study, published in Journal of Cell Biology (April 2006), researchers have found that location of an RNA-degrading enzyme is key to its role in cell cycle regulation.

"Since we know that abnormal cell growth and behavior lead to cancer, it is important that we learn as much as we can about cell cycle regulation and what impact it has on degrading RNAs, as these issues play a significant role in developing our understanding of inhibitory drugs for the treatment of cancer," said Mark E. Schmitt, Ph.D., principal investigator of the study and associate professor of biochemistry and molecular biology at SUNY Upstate.

The location of mitochondrial RNA processing (RNase MRP) is cell-cycle controlled, researchers found. During the cell division process, RNaseMRP localizes to the nucleolus. In this location, it is not exposed to mRNAs and therefore cannot degrade mRNAs. However, immediately following the initiation of mitosis, when the chromosomes start to separate, RNaseMRP begins the degrading of mRNAs and ends the cell division process.

What researchers discovered was that with the beginning of mitosis, the RNaseMRP relocates to the punctuate spot in the cytoplasm to begin its work in degrading mRNAs.

Earlier research by Schmitt and his team showed that RNaseMRP degrade mRNAs that encode a specific class of regulatory molecules called B-cyclins.

The degrading of RNAs is essential to keeping the cycle cell regulation on track.

Marion Zatz, program director with the National Institute of General Medical Sciences (NIGMS), applauded the efforts of Schmitt and his team in creating new understanding of cell cycle regulation. "Most cell cycle regulation relies on changes in protein levels and activities, Zatz said. "Dr. Schmitt's studies reveal a new level of spatial and temporal cell cycle regulation by RNA degrading enzymes."

The SUNY Upstate study was funded by NIGMS.

SUNY Upstate coauthors with Schmitt include Tina Gill and Jason Aulds.