Fig 8.

Depletion of RVBs makes TIP60 complex heat labile. Flag-TIP60.com purified from cells transfected with either siControl (GL2) (A and B), siRVB1 (C and D), or siRVB2 (E and F) was preincubated at 30°C for indicated minutes prior to an in vitro HAT assay on histone H4 for 20 min. Immunoblotting of reaction products with the indicated antibodies is shown. (A) Western blots show that the HAT activity of TIP60.com from siControl-transfected cells is stable to heat challenge. (B) The graph shows the relative amount of AcH4 relative to total H4 as in panel A, with 1 being the acetylation seen with 0 min of heat challenge. The x axis shows time of heat challenge in minutes as indicated. (C and E) Western blots for an experiment similar to that for panel A, except cells RVB1 and RVB2 depleted. (D and F) Graphs for AcH4 relative to total H4 in panels C and E, respectively.