FIG. 4.
Pho4-induced remodeling at the PHO5 promoter in vitro is similar to but less extensive than in vivo. (A) Same as Fig. 3A but with in vivo samples from wild-type strain CY337 corresponding to the repressed (+Pi) and induced (−Pi) states of the PHO5 promoter electrophoresed alongside in vitro samples. Note that the vertical bar between lanes 6 and 7 highlighting the in vitro hypersensitive region is interrupted by a short stippled stretch at a position of DNA protection that is fully accessible in the induced state in vivo (bar between lanes 8 and 9). (B) ClaI accessibility values for in vitro-assembled chromatin treated as indicated. For columns 4 to 12, Pho4 and/or Pho2 were added after the salt gradient dialysis chromatin was incubated with yeast extract. For columns 13 to 16, they were added together with the yeast extract. Error bars show the variation of two or three independent experiments starting from the same salt gradient dialysis chromatin preparation. In the case of three experiments, the error bars correspond to the standard deviation.