MEDFORD/SOMERVILLE, Mass. - In the past 10 years, researchers in genome stability have observed that many kinds of cancers are associated with areas where human chromosomes break. More recently, scientists have discovered that slow or altered replication causes chromosomal breaking. But why does DNA replication stall?
In a Tufts University study published in the July 14 issue of "Proceedings of the National Academy of Sciences of the United States of America," a team of biologists have found a relationship between peculiar DNA sequences named palindromes and replication delays.
Sergei Mirkin, White Family Professor of Biology at Tufts' School of Arts and Sciences, along with his graduate student Irina Voineagu and collaborators Kirill Lobachev and Vidhya Narayanan from the Georgia Institute of Technology explored the heretofore elusive function of long palindromes in DNA replication. Mirkin's research was funded by the National Institutes of Health.
Mirkin and his team studied palindrome behavior in bacterial, yeast and mammalian cells because they allowed them to monitor DNA replication in a more detailed way than looking at actual human chromosomes. Based on previous studies in model systems, they expect their results to be applicable for human chromosomes.
Abnormally shaped DNA blocks molecule's replication
In the context of everyday life, palindromes are quite common, said Mirkin. They are words, phrases, numbers or other sequences of units that read the same way in either direction. "We all enjoy palindromes in everyday language, such as 'A man, a plan, a canal Panama!' They are short, make perfect sense and are easy to remember," he explained. The problems begin when they become longer. "They stop making sense," he said. "For example, say 'A man, a plan, a cat, a ham, a yak, a yam, a hat, a canal-Panama!'"
Past DNA research had shown that long palindromes change the shape of the molecule f
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