UASt regulates expression of residues 1-421 of the 2N4R form of Hsap\MAPT, mimicking the full-length form truncated at the Asp421 site, and in which 14 Ser/Thr sites (Thr111, Thr153, Ser175, Thr181, Ser199, Ser202, Thr205, Thr212, Thr217, Thr231, Ser235, Ser396, Ser404 and Ser422) are changed to alanines mimicking non-phosphorylation. Phosphorylation status affects pathogenicity in human patients and the truncated form is associated with Alzheimer's Disease.
Expressing Hsap\MAPTAP421.UAS under the control of Scer\GAL4GMR.PF leads to a rough eye phenotype on the posterior part of the eye, with disruption of the photoreceptor organization. Expression under the control of Scer\GAL4Gad1.3.098 leads to decreased locomotion (decreased walking distance, speed and increased wobbling).