FIGURE 1.

DJ-1β knockdown does not affect the response of S2 cells to methylglyoxal challenge. A–A′, S2 cells express detectable DJ-1β but not DJ-1α. mRNA levels detected by quantitative RT-PCR, normalized to rp49, and compared with mRNA from adult males, which express both DJ-1α and DJ-1β. B–D, DJ-1β knockdown does not affect the viability of S2 cells in response to methylglyoxal challenge. S2 cells were treated with a non-targeting negative control dsRNA (lacZ), or dsRNAs targeting glyoxalase Glo1 as a positive control, DJ-1β, or Glo1 and DJ-1β combined. Glo1 dsRNA efficiently knocks down Glo1 protein (C) and activity (C′). DJ-1β knockdown efficiently depletes DJ-1β protein (D). Cells treated with indicated MG concentrations for 48 h were scored for viability via an MTT assay, showing that Glo1 knockdown leads to reduced ability to withstand MG whereas DJ-1β knockdown does not (B–B′). All data points were measured in biological quadruplicates, and the experiment was repeated four times. Error bars: Std. Error (B′), Std. Dev. (C′). E, addition of 1 mm methylglyoxal to S2 cells results in increased levels of the MG adduct CEL only in Glo1 knockdown cells but not in DJ-1β knockdown cells.