Fig. 2.
Decreased PSII quantum yield and reduced levels of PSI polypeptides in the cgl71 mutant. (A) Quantum yield of PSII based on the fluorescence parameter ΦPSII, which is (Fm′ − Fs)/Fm′, in WT, cgl71, and the cgl71(CGL71) rescued strains. Cells used for the analyses were in exponential growth phase under LO conditions. For measurements, samples were exposed to 1 min of actinic light at the intensities indicated on the x axis. All values on the y axis are averages of three separate measurements (biological replicates). (B) Chlamydomonas proteins from WT, cgl71, and the cgl71(CGL71) rescued strain were resolved by SDS/PAGE on a 15% polyacrylamide gel and detected immunologically. Antibodies used for the analysis were to the polypeptides indicated at the right side of the figure. One microgram of chl was loaded for each sample analyzed. The boxed area highlights the subunit polypeptides of PSI. See Materials and Methods for more details. AtpB, β subunit of ATP synthase; LHCA1, light-harvesting polypeptides of PSI; LHCB2, light-harvesting polypeptide of PSII; PetA, cytochrome f; PsaA, PsaC, PSAD, and PSAH, polypeptide subunits of PSI; PsbB, chlorophyll protein of PSII; RbcL, large subunit of ribulose 1,5 bisphosphate carboxylase; Ycf3 and Ycf4, assembly factors associated with PSI.