RNA Polymerase I Transcription Factor homolog (RRN3)

RRN3 cDNA rescued a lethal deletion of RRN3 when expressed in the mutant yeast. Thus, unlike other Pol I transcription factors, RRN3 is functionally conserved between yeast and mammals. A point mutation of an amino acid that is conserved between the yeast and human proteins compromised the function of each vector, confirming that the observed sequence similarity is functionally significant.stress-dependent inhibition of Pol I was mediated by inactivation of the Pol I-specific transcription factor TIFIA in mammalian cells. Inactivation was due to JNK2 (MAPK9) phosphorylation of TIFIA at residue thr200, which impaired TIFIA interaction with Pol I and the TBP-containing complex TIFIB/SL1, thereby abrogating initiation complex formation.