Figure 4. Stability of SPT16 and SSRP1 proteins is reduced under conditions of mRNA depletion.(A)Lysates were prepared from HeLa cells treated with 100 ng/ml actinomycin D (ActD) or 50 μg/ml cyclohexamide (CHX) for the amount of time indicated above each lane and analyzed by western blotting with antibodies against SPT16, SSRP1, or β-actin.(B)Quantitation of the intensities of the bands in (A) corresponding to SPT16 and SSRP1 proteins normalized using the intensity of β-actin bands. The normalized intensity at ‘time 0’ was set at 1.0.