UASt regulatory sequences drive expression of a Hsap\CDK19 cDNA that has been mutated to carry a Y32H amino acid substitution (this variant has been identified in an individual with a syndromic neurodevelopmental disorder). The coding sequence is tagged at the C-terminal end with three copies of the Tag:HA epitope and is flanked by a pair of incompatible FRT sites (FRT5 and FRT2), which allows for future in vivo exchange of either the promoter or tag sequence.