The Rpb4d189 mutation results in early lethality; Df(3R)d189 homozygotes in which the function of all genes affected by the deficiency except Rpb4 have been rescued using P{CaSpeR4-Dtl+Ada2a+} show first larval instar lethality.
Polr2Dd189/Polr2Dd189 is a non-suppressor of polytene chromosome puff phenotype of Fcp1RNAi.UAS.WIZ, Scer\GAL4Act5C.PI
The puff in the 61C region induced by Scer\GAL4Act5C.PI-mediated expression of P{UAS-Fcp1.dsRNA.WIZ}61C remains readily detectable in Rpb4d189 homozygotes.