A TI{KozakGAL4} DNA cassette has been inserted into Rat1, replacing the coding sequence (coordinates of deleted sequence are 2L:6908087..6911000 , release 6 genome). This results in a simultaneous knock-out of Rat1 plus a knock-in of GAL4 that is expected to be expressed under the control of the endogenous regulatory sequences of Rat1 (predicted to gene trap all annotated transcripts of the gene). The 5' end of the deletion associated with the insertion is 243 bp upstream of the 5' end of the Polr1F gene and may affect its transcription. The 3' end of the deletion associated with the insertion is 90 bp downstream of the 3' end of the Wee1 gene and may affect the proper 3' end formation of its transcripts. The TI{KozakGAL4} cassette was inserted via the CRISPR/Cas-9 drop-in technique, using a dsDNA donor vector with homology arms of length 200bp. The sgRNA sequences used to target the gene were: CATTGATCGGAGCATGCTTGTGG and GAACTTGGCATGAGTTTGTTTGG.