DNA Methylation Affects the Efficiency of TALEN-mediated Genome Editing in Rice

Transcription activator-like effector nucleases (TALENs) are one of the most prevalent SSNs and have a potential to provide higher target specificity. However, they are sensitive to methylated cytosines that are present in transposons and active genes in plants. In mammalian cells, the methylation sensitivity of TALENs could be overcome by using a base-recognition module (N^∗) with a higher affinity to methylated cytosine. However, the effectiveness of N^∗ module in plants has not been explored.

Researchers from the National Agriculture and Food Research Organization in Japan designed sets of TALENs with or without N^∗ modules and examined their efficiency in genome editing of methylated regions in rice. Although improvement in genome editing efficiency was observed with N^∗-TALENs designed for a stable methylated target, other targets carrying cytosines with various levels of methylation showed resistance to both normal and N^∗-TALENs.

The results suggest that variability of cytosine methylation in target regions is an additional factor affecting the genome editing efficiency of TALENs.

For more on this study, read the article in Frontiers in Plant Science.