Sequence between the first intron and 3'UTR of the ci locus has been replaced with mutated genomic ci sequence, removing the w+* marker present in TI{TI}ciw+ and reconstituting a ci locus that carries clustered point mutations in the three principal regions that bind rdx (this set of mutations has previously been shown to render ci largely insensitive to rdx in a tissue culture assay). The inserted sequence also contains a Tag:FLAG and a Tag:HA tag, upstream and downstream of the ci coding sequence respectively.