Figure 3.

Specific DNA binding by RIP60 is located in both hands Z1 and Z2. (A) Schematic representation of RIP60 (Z123) showing the organization of hands Z1, Z2, Z3 and the proline-rich region. (B) Analysis of RIP60 DNA binding activity by gel mobility shift assays. GST fusion proteins containing hands Z1, Z2 or Z3 were expressed in E.coli, purified and analyzed for DNA binding activity. Because expression of full length RIP60 in E.coli was difficult, analysis of RIP60 binding activity was conducted with nuclear extracts from cells transfected with pCMV-HA-RIP60 (see Results). Binding specificity was assessed by competition with the DSR RIP60 binding site, an intron binding factor site (IBF), or the AT-rich regions from either the SV40 or polyomavirus origins of replication.