FIG. 2.

GAG polymerases and HSPGs are required for the binding of ACP to S2 cells. (A) S2 cells were untreated or treated with dsRNA sequences targeting the GAG polymerase genes ttv, DEXT2 (sotv), and both ttv and DEXT2 (sotv) or with control sequences targeting the GFP gene, smo (encoding smoothened, a transmembrane receptor that binds to the segment polarity protein Hedgehog), or mnb (encoding minibrain, a serine/threonine protein kinase) prior to incubation with Alexa Fluor 488-labeled ACP. Data are shown as the MFI ± SE relative to that for the sample treated with dsRNA targeting GFP in each repetition of the experiment. The targeting of either the ttv or DEXT2 (sotv) polymerase reduced the binding of ACP compared to that by cells that were untreated or treated with control dsRNA sequences (targeting the GFP gene, mnb, or smo). The targeting of ttv (P = 0.06 versus results for the targeting of the GFP gene; Student's t test) had greater effect than the targeting of DEXT2; this effect was augmented by targeting DEXT2 in addition to ttv (P < 0.001). (B) Drosophila S2 cells were untreated or treated with dsRNA sequences targeting individual HSPGs (sdc, dally, and dally-like protein) or HSPGs in combination (sdc and dally, sdc and dally-like protein, dally and dally-like protein, and sdc, dally, and dally-like protein) or with control sequences (targeting the GFP gene, mnb, or smo) prior to incubation with Alexa Fluor 488-labeled ACP. The targeting of each HSPG alone, or of any combination of HSPGs, reduced the binding of ACP.