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. Author manuscript; available in PMC: 2010 May 11.
Published in final edited form as: Mol Cell. 2008 Jul 25;31(2):244–254. doi: 10.1016/j.molcel.2008.06.004

Figure 3. β-lapachone potently and selectively inhibits the SMN complex-mediated snRNP assembly in vitro and in cells.

Figure 3

(A) Chemical structure of β-lapachone.

(B) Concentration-dependent inhibition of SMN complex activity by β-lapachone in cells. HeLa cells were treated with various concentrations of β-lapachone or with DMSO (control) for 1 hour. SMN complex activity in extracts from treated cells was measured using magnetic beads snRNP assembly assay and compared to DMSO-treated control cells (100% activity). IC50 was calculated from the dose-reponse graph. Error bars represent SDs from 3 independent measurements.

(C) β-lapachone selectively inhibits SMN complex-mediated Sm core assembly. Assembly reactions were performed using either cell extracts or purified native snRNP proteins lacking the SMN complex (Sm proteins). Both samples were adjusted to contain a similar amount of Sm proteins. Magnetic beads snRNP assembly assay was carried out with U4 or control U4ΔSm snRNA in the presence of either 20 or 100 μM β-lapachone or DMSO control. Sm core assembly on U4 snRNA in the presence of DMSO was considered 100% activity. The error bars represent SDs from 3 independent measurements.