Baseline levels of activated MPK-1 in the gonad are reduced in <i>rpoa-2(op259)</i> and do not increase upon irradiation.

<p>A) Gonads were extruded from non-irradiated (0 Gy) and irradiated (60 Gy) adult worms 4 hours after treatment, fixed, and immunostained for the doubly phosphorylated (activated) MPK-1. MPK-1 activity is high in the late meiotic pachytene region (white dashed lines) and is further increased following IR in wild-type worms, but not in <i>rpoa-2(op259)</i> mutants. Control staining included total MPK-1 with anti-ERK, and anti-dsDNA to detect an epitope other than protein for normalisation of fluorescence intensity. Size bar, 40 µm. B) Quantification of the anti-ppMPK signal intensity along the central axis (white streak) of the late meiotic pachytene region, starting distally to the first oocyte (white dashed reference line) and extending into the mid-pachytene region. Profiles were plotted for at least 8 worms per condition (thin grey lines for individual wild-type worms, thin green lines for individual <i>rpoa-2(op259)</i> mutants) and a spline was calculated from their overlay. Size bar, 25 µm.