A readthrough reporter cassette has been inserted immediately 5' of the stop codon of ORF2 in the endogenous kel locus. The reporter cassette consists of three copies of the Tag:FLAG epitope, a T2A sequence and a ' NLS::tdGFP ' open reading frame (encodes nuclear-localized tandem dimer GFP). The reporter cassette allows for specific detection of the readthrough product using either the Tag:FLAG epitopes at the C-terminus of ORF2, or detecting the presence of the NLS::tdGFP protein (the presence of the T2A sequence results in the NLS::tdGFP marker being produced as a separate protein following readthrough translation).