Fig. 7. Effects of pH on subcellular localization of p26 and transcription rates. Homogenates of control embryos were incubated in buffer K at pH6.5 to move p26 into nuclei, or at pH8.0 to keep p26 extra-nuclear. Nuclei were then isolated from both homogenates for further study. (A) Nuclei isolated from embryos homogenized at either pH8.0 (C, control) or pH6.5 (L, p26-loaded) were used in a 15min mock run-on assay. Samples of nuclei were prepared for SDS–PAGE at both initiation (C0, L0) and termination (C15, L15) of the assay. Equal amounts (1x106 nuclei) were loaded per lane, and the arrow indicates p26. (B) Detection of p26 in the samples from part A by western immunoblotting. (C) Transcription rates of nuclei isolated from homogenates incubated at pH8.0 and pH6.5. Nuclear run-on assays were carried out as described in Materials and methods, at the indicated pH. Error bars are +1 S.D. based on three separate experiments.
