Fig. 2

MDM2 and HDM2 bind poly(G) RNA when immunoprecipitated from Sf9 insect cell lysates overexpressing these proteins (A) and binding of MDM2 to poly(G) RNA decreases with increasing NaCl concentration and is not competed with excess yeast RNA or poly(dI-dC) (B)

(A) Immunoprecipitations were performed from Sf9 lysates that were uninfected, infected with a wild-type AcMNPV baculovirus, or recombinant baculoviruses which overexpress MDM2 or HDM2 as indicated. Each lysate was immunoprecipitated with 2 negative control mAbs (419, 421) and 3 mAbs specific for MDM2 and HDM2 (2A10, 4B11 and 4B2). The beads were washed and incubated with [³²P] end-labeled poly(G) RNA in an RNA-binding buffer. The beads were then washed and counted in a scintillation counter. (B) Sf9 lysate overexpressing MDM2 was immunoprecipitated with 419, 421 (Columns 1 and 2) or 4B11 (Columns 3–16). RNA-binding reactions were performed with increasing NaCl concentration, with excess yeast Torula RNA, and excess poly(dI-dC) as indicated