rna polymerase in in macronuclei of late log-phase cells of the ciliate tetrahymena pyriformis is found to be present in 2 functional states , the one being actively engaged in transcription of ribosomal genes , the other one in a `` '' free '' '' state , i.e . free to transcribe added dna or poly d ( at ) .
C0007634
cells
C0035553
ribosomal