Rogue DNA Fragments

Create genomic instability common in cancer

Published in Nature, the study reveals that when the enzyme Dna2 is absent, the genetic material of a cell becomes unstable and the DNA breaks.

While evaluating a key mechanism that assists in DNA repair, a team of researchers confirmed a key mechanism for disruptive DNA insertion. Baylor College of Medicine’s Grzegorz Ira, PhD, and Yang Yu, PhD, and Houston Methodist’s Kaifu Chen, PhD, and Bo Xia, PhD, collaborated with researchers from the University of Texas MD Anderson Cancer Center and Weill Cornell Medical College to make a discovery that led to publication in December 2018’s Nature. They found that when the mechanism—the enzyme Dna2—is absent, the genetic material of a cell, the genome, becomes unstable and results in breaks in DNA. Picture the double helix of a DNA strand, then imagine both strands are broken and one of the tools that typically repairs it is missing. Now the cell is threatened. Without the Dna2 repair tool evaluated in this study, excess pieces of DNA produced during cell replication can insert themselves and alter the genome, often negatively impacting a cell. Inserted DNA fragments are often duplications of an existing DNA sequence that are released and subsequently integrated into areas of double strand DNA breaks. Importantly, DNA insertions also play a role in the mechanisms for antibody diversification, which can help protect humans from pathogens.

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