BIOL 367 Chapter Notes - Chapter 10: Caat Box, Transcription Factor Ii D, Sv40
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The named the 3 peaks of polymerase activity in order of their emergence from the ion-exchange column. Polymerase i s indeed located primarily in the nucleolus, and polymerases ii and iii are found in the nucleoplasm very likely that pol i is the rrna- synthesizing enzyme. Polymerase ii makes an ill-defined class of rna known as heterogeneous nuclear rna (hnrna) as well as the precursors of micrornas (mirnas) and most small nuclear rnas (snrnas) Polymerase iii makes precursors to the trnas, 5s rrna, and some other small rnas. At very low concentrations, alpha-amanitin inhibits polymerase ii completely while having no effect at all on polymerase i and iii. At 1000-fold higher concentrations, the toxin also inhibits polymerase. The three polypeptides, rpb1, rpb2 and rpb3 are all absolutely required for enzyme activity. Thus phosphorylation of the ctd appears to accompany the transition from initiation to elongation. The evidence strongly suggests that iia (the un-
