A chimeric construct encoding full length N with the Scer\GAL4 DNA-binding domain (amino acids 1 to 147) inserted 27 codons carboxy terminal to the transmembrane domain is separated from ftz regulatory sequences (nucleotides -669 to + 70) by an FRT cassette containing the Ecol\lacZ coding region followed by a polyadenylation signal. Five copies of the Tag:MYC tag are inserted at the N-terminal end of the Scer\GAL4 sequences.