Overexpression of Int6 causes elevated
Pap1-responsive gene expression without Pap1 relocalization. (A)
Transformants of S. pombe h-
leu1–32 (pap1+) or
h-
pap1::ura4+ ura4-D18
leu1–32 (pap1Δ) containing either pREP3X, or
pREP3X cDNA library plasmids directing expression of full length Int6
or Int6CT, as indicated, were grown in liquid culture for 16 h at
30°C in the absence of thiamine and were processed for northern or
western blotting. A northern blot was probed to detect
apt1 and trr1 RNA and subsequently
stripped and reprobed to detect act1 RNA as a loading
control, as indicated. A western blot of whole cell extracts prepared
from the same cultures was probed with antibodies directed against
Pap1, p25 and Cdc2 (loading control) as indicated. (B and C) An
h- leu1–32 ura4-D18 strain
transformed with pREP42-GFP-Pap1 and either pREP3X (B)
or pREP3X-int6 (C) was grown in minimal medium without thiamine for
24 h in the dark at 25°C. GFP-Pap1 was visualized by confocal
laser microscopy. Scale bar, 10 μm.