Figure 4.

PSII core subunits and PSII complexes are destabilized in VIGS-OHP2 plants. A, Western-blot analysis of PS core subunits and the two major LHC proteins LHCA1 and LHCB1 in the VIGS lines. Total proteins were separated on acrylamide gels containing 6 m urea, transferred onto nitrocellulose membranes, and probed with specific antibodies. The large subunit of Rubisco (RbcL) is shown as a loading control. B, BN-PAGE analysis of thylakoid membranes. Thylakoid membranes representing equal amounts of chlorophyll (8 µg) were solubilized with 1% DMM, and photosynthetic complexes were separated on 4.5% to 12% BN gels. C, Fractionation of photosynthetic complexes under denaturing conditions in the second dimension. Lanes from BN gels were denatured and layered on top of acrylamide gels containing 6 m urea. After electrophoresis, proteins were transferred onto nitrocellulose membranes and probed with specific antibodies. PSII-containing complexes are labeled at the bottom edge of the D1 blots: PSIIsc, PSII supercomplexes; PSIId, PSII dimer; PSIIm, PSII monomer.