Intron with transgenic marker (InTraM) facilitates high-throughput screening of endogenous gene reporter lines

The generation and maintenance of genome edited zebrafish lines is typically labor intensive due to the lack of an easy visual read-out for the modification. To facilitate this process, we have developed a novel method that relies on the inclusion of an artificial intron with a transgenic marker (InTraM) within the knock-in sequence of interest, which upon splicing produces a transcript with a precise and seamless modification. We have demonstrated this technology by replacing the stop codon of the zebrafish fli1a gene with a transcriptional activator KALTA4, using an InTraM that enables red fluorescent protein expression in the heart.