FIG. 2.

Rbg1 associates with polyribosomes. (A) Whole-cell extracts from strain W303 were resolved by density sedimentation in 7 to 47% sucrose gradients. (B) Polyribosomes were disrupted by the addition of micrococcal nuclease (5 U/μl) prior to loading of extracts on gradients. The UV absorbance trace (254 nm) obtained during fractionation is shown with the positions of the 40S, 60S, 80S, and polyribosomes indicated. Fractions (numbered) were analyzed by immunoblotting with antibodies against Rbg1, Rbg2 and S2, a small ribosomal subunit protein, as indicated. L, 1/100 cell extract loaded on gradient.