Mutated sequence encoding Atpα exons 2-6b has been inserted into the attP site present in TI{TI}AtpαΔ2-6b, reconstituting a complete Atpα transcription unit that carries the Q111T and A119S amino acid replacements. A single attR site and a single loxP site remain in the reconstituted Atpα locus (in the intron upstream of exon 2).