The Influence of Non-Steroidal Anti-Inflammatory Drugs on Quasi-Palindrome Driven Template-Switch Mutagenesis in Escherichia coli

Abstract

Quasi-palindrome regions are characterized by almost perfect inverted repeats of DNA bases which can form secondary structures known as hairpins1. These structures are found in nature and have been found to interfere with important cellular events such as replication and transcription regulation. Harpins are known to block DNA replication. Once DNA replication is blocked by these DNA structures, the DNA replication fork needs to find a solution to continue to replicate the DNA. At some frequency, DNA polymerase (responsible for replicating the DNA) can use alternative DNA strands as template to make more DNA2,5. One alternative method is called “Template-switching” and it results in a mutation that creates a perfect palindrome from a quasi-palindromic sequence3,4. This class of mutation has been associated with multiple human diseases, including osteogenesis imperfecta and cancer. FDA approved non-steroidal anti-inflammatory drugs are commonly used to treat many different types of human ailments6. Although we know different mechanisms of how these drugs work, we have yet to understand how they interfere with DNA polymerase during DNA replication at QP regions. Using a library of 300 FDA-approved drugs, we aim to assess the propensity of QP mutations after exposure of chemicals - known to block or stall DNA polymerase. Using a QP mutation reporter in E. coli, we are screening hundreds of drugs for their ability to promote QP mutations3,4. Elucidating the consequences of these drugs in template-switching QP mutations is essential in providing full understanding of the potential side effects for the current FDA-approved drugs.