An α-tubulin promoter drives expression of a mutated form of ens in which the putative 14-3-3 protein binding sites have been mutagenised. STS and SSS starting at amino acid positions 168 and 198, respectively, have each been replaced with AAA, creating AscI or NotI sites. The four putative sites from amino acids 307 to 341 have been removed by deletion and have been replaced with AR, creating an XbaI site.