Fig. 2

Effect of various regulatory elements on Cel6A accumulation in C. reinhardtii transplastomic strains. Immunoblots showing the Cel6A protein accumulation in C. reinhardtii strains expressing the cel6A, NPTII-cel6A, and TetC-cel6A genes under the regulation of the atpA promoter and 5′UTR (top blot) or the 16S promoter and atpA 5′UTR (bottom blot) constructs. Extended exposure time to X-ray film, up to several hours, was used for the top blot, while short exposure time, 1–2 min, was used to observe the immunoreactive bands in the bottom blot. All lanes contained 50 µg total soluble protein (TSP) extracted from the wild-type and transplastomic C. reinhardtii strains. Lanes A and B contain protein extracted from two independent transplastomic single colony isolates. Control lane contained 0.1 µg purified Cel6A protein. Quantification of the Cel6A concentration in the algal extracts was done by comparing the relative blot density of bands to those of the purified Cel6A control