mScarlet replacement of mir-266 pre-miRNA. A cassette containing mScarlet-I and an SEC flanked by lox2272 was introduced into the mir-266 loci using CRISPR/Cas9. This line was generated by excising SEC leaving the SL1::EGL13NLS::mScarlet-I::cMycNLS::let-858 3' UTR transcriptional reporter in the loci.