COLUMBUS, Ohio, April 4 (UPI) -- U.S. scientists have discovered how an unusual protein helps a cell avoid damage when making new DNA, thereby averting the cell's self-destruction.
But the Ohio State University researchers said they also discovered the protein -- an enzyme called Dpo4 -- often makes errors when copying the genomic DNA sequence that later might cause the cell to become cancerous.
"Unrepaired DNA damage presents a big roadblock for the DNA replication machinery, which cannot go around it," said Zucai Suo, an OSU assistant professor of biochemistry, noting such damage triggers cell death because the DNA is not replicated.
Dpo4 is one of a family of enzymes called Y-family DNA polymerases that were discovered about 10 years ago and are only now becoming understood.
"These enzymes provide a survival mechanism for cells," added the study's first author, graduate student Kevin Fiala. "They allow DNA replication to continue, so the cell doesn't die. But they don't repair the DNA damage that exists."
The findings are described in two back-to-back papers in the current issue of The Journal of Biological Chemistry.
