FlyBase curator comment: TI{GAL4} represents a DNA segment that encodes GAL4 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, producing a transcriptional fusion that is expressed under the control of the regulatory sequences of the trapped gene. If the inserted TI{GAL4} sequence is in the correct orientation and frame, the GAL4 sequence can be translated. In some cases, this could result in GAL4 being expressed as a fusion protein with coding sequence from the trapped locus. However, in many cases, this is avoided by inserting the TI{GAL4} sequence at the translational start of the endogenous locus and also either deleting the endogenous open reading frame as part of the targeted mutagenesis and/or including a stop codon downstream of the inserted GAL4 coding sequence. 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{GAL4}, see the description in the insertion report and in any allele reports associated with that insertion.