FlyBase curator comment: TI{Cas9-2A} represents a DNA segment which contains sequence encoding Cas9 followed by a viral 2A-like peptide and which has been inserted into the genome via any technique (such as CRISPR/Cas9 or other targeted mutagenesis) that results in the inserted DNA not being flanked by transposable element ends. This sequence can act as a promoter trap element when it is inserted into an exon of an endogenous locus; if the insertion is in the correct orientation, Cas9 will be expressed under the control of the regulatory sequences of the trapped gene. The presence of the viral 2A-like peptide (which promotes ribosomal 'skipping') ensures that Cas9 is translated independently and not as a fusion protein with any downstream coding sequence of the endogenous locus. Other sequences may be present in the inserted DNA and the precise sequence inserted may differ for different insertions of the construct. For details of what is inserted into the genome for an individual insertion of TI{Cas9-2A}, see the description in the insertion report and in any allele reports associated with that insertion.