Figure 1.

Immunodetection of C1 and C3 levels in wild-type cells grown at different temperatures shows differences in the case of C3. A, Cells were grown at 18°C, 23°C, and 28°C and harvested during early day (LD2) and early night (LD14). Crude extracts were prepared, and proteins (100 μg per lane) were separated by 9% SDS-PAGE along with a molecular mass standard and immunoblotted with anti-C1 antibodies (see “Materials and Methods”). Asterisks indicate a possible modified form of C1. Densitometry quantifications were done with three independent experiments (see “Materials and Methods”). Therefore, the amount of C1 detected in cells grown at 23°C and harvested at LD2 was set to 100% and used as reference. B, The same procedure described for A was carried out, but immunoblotting was done with anti-C3 antibodies (see “Materials and Methods”). C, A random nonspecific Coomassie blue-stained band from a duplicate gel shows that similar amounts of proteins were loaded.