UASt regulatory sequences drive expression of atl carrying a R192Q amino acid substitution; this mutation is equivalent to a R217Q change in the orthologous human ATL1 gene, a pathogenic variant associated with SPG3A (an autosomal dominant form of hereditary spastic paraplegia) and the change has previously been shown to result in a protein that is completely defective in dimerization, GTPase and fusion activities. The coding sequence is tagged with Tag:MYC.