UAS regulatory sequences drive expression of a C-terminally truncated form of Fmr1 which is fused at the C-terminal end to a RKRTRRKRTWRRLQRKRRSLPNR peptide sequence. This sequence has been identified as a novel amino acid sequence caused by a frameshift mutation in the human FMR1 gene of a patient with fragile X syndrome and it has been shown to contain a nuclear localization signal.