Csas at the endogenous locus, tagged at the C-terminal end with EGFP. The tag sequence is preceeded by the linker sequence "AYALMKEYYVILSSSSGSSLEVLFQPGSGSGS" where AYA is derived from the cloning procedure, LMKEYYVILSS is the translated RSRT recombinase target site, SSGSS are linker residues, LEVLFQP is the PreScission Protease cleavage site and GSGSGS are linker residues. Generated by RSR-mediated excision of the RSRT cassette present in the TI{T-STEP.TagRFP-T} insertion of CsasKI.