Here, we investigated the utility of a system in which individual chains of recombinant procollagen VII that were tagged with either GFP or with monomeric red fluorescent protein (RFP) were co-expressed in the same cells. The rationale for creating such a system was to express heterogeneous mutant procollagen VII molecules consisting of wild type α chains and chains that harbor a single amino
apexbio substitution in a way similar to the expression pattern seen in patients with dystrophic epidermolysis bullosa (DEB), a heritable blistering disease of skin [16] and [17]. Our biochemical and microscopic assays demonstrated that the presence of two different fluorescent proteins at the C-termini of the α chains does not prevent co-assembly of these chains into heterogeneous triple-helical
molecules and does not alter the secretion of these GFP and RFP-tagged molecules into the extracellular space. Our study provides a basis for employing fluorescent proteins as tags for complex collagenous proteins of the extracellular matrix.
