Mini singlet oxygen generator (miniSOG) is a genetically encoded 106 amino-acid protein producing reactive oxygen species upon illumination of blue light [1]. MiniSOG has been used to ablate cells and inactivate protein functions [2, 3]. Reactive oxygen species are known to cause DNA damage, and such damages may cause heritable changes. To test if miniSOG can mutagenize genomic DNA in vivo, we fused miniSOG to HIS-72, the C. elegans orthologue of histone 3 (His-mSOG), and expressed it in the germline. These animals behaved and reproduced normally under ambient light. Following blue light treatment, we observed heritable mutations in the F2 progeny, such as dumpy and uncoordinated. We optimized His-mSOG-induced mutagenesis using a suppressor screen of paralyzed
rpm-1(lf);
syd-2(lf) mutants [4]. By quantitating the mutation frequency, we found that the His-mSOG-induced mutation rate was highest when gravid young adults were treated. Analyses of whole-genome and Sanger sequencing showed that His-mSOG induced variable mutations including single-nucleotide substitutions, deletions and a transposon insertion with a strong bias towards G:C to T:A substitutions, which are reported to be a major type of mutations in bacteriophage induced by singlet oxygen [5]. His-mSOG mutagenesis could also cause chromosomal integrations of extrachromosomal arrays at the rate comparable to Psoralen-UV mutagenesis. We envisage that His-mSOG may be combined with other techniques for genome manipulation. [1] Shu, X., et al., PLoS Biol, 2011 [2] Lin, J.Y., et al., Neuron, 2013 [3] Qi, Y.B., et al., PNAS, 2012 [4] Noma, K., et al., Genetics, 2014 [5] Decuyper-Debergh, D., et al., EMBO J, 1987.