lexAop and UAS regulatory sequences and a minimal Hsp70 promoter (derived from the pUASTLOTattB vector) are fused upstream of a fusion protein that encodes an antibody-based Tag:HA trap that localizes to the extracellular matrix of the basal lamina. The fusion protein comprises the vkg coding sequence, with a sequence cassette that encodes mCherry and the scFv(antiHA-X15F11) single-chain antibody inserted between the first and second exon. The lexAop and UAS regulatory sequences are flanked by loxP and lox2272 sites respectively (meaning that the P1cre recombinase can be used to excise one of the enhancers in a mutually exclusive manner if desired).