zo RNA polymerases come in s different forms, but share many features RNA polymerases performs essentially the same reaction in all cells a Bacteria have only a single 9 RNA polymerases while in 6 eukaryotic cells there are three: RNA Pol I, II and III 11
11 RNA polymerases come in different forms, but share many features ◼ RNA polymerases performs essentially the same reaction in all cells ◼ Bacteria have only a single RNA polymerases while in eukaryotic cells there are three: RNA Pol I, II and III RNA polymerase and the transcription cycle
rna Pol II is the focus of eukaryotic transcription, because it is the most studied polymerase, and is also responsible for transcribing most genes-indeed, essentially all protein-encoding genes a RNA Pol I transcribe the large ribosomal RNa precursor gene a RNA Pol III transcribe tRNA gene, some small nuclear RNA genes and the 5s rRNA genes 12
12 ◼ RNA Pol II is the focus of eukaryotic transcription, because it is the most studied polymerase, and is also responsible for transcribing most genes-indeed, essentially all protein-encoding genes ◼ RNA Pol I transcribe the large ribosomal RNA precursor gene ◼ RNA Pol III transcribe tRNA gene, some small nuclear RNA genes and the 5S rRNA genes
Table 12-1: the subunits of RNA polymerases Prokaryotic Eukaryotic Bacterial Archaeal RNAP I RNAP lI RNAPⅢ Core Core (Pol D) Pol Ill) A/A RPA1 RPB1 RPC1 RPA2 RPB2 RPC2 D RPC5 RPB3 RPC5 RPC9 RPB11 RPC9 K RPB6 RPB6 RPB6 [+6 others [+9 others [+7 others [+11 others 13
13 Table 12-1: The subunits of RNA polymerases
The bacterial RNa polymerase The core enzyme alone synthesizes RNA 14
14 The bacterial RNA polymerase The core enzyme alone synthesizes RNA a a b b’ w
prokaryotic Fig 12-2 RNAP Comparison The same color indicate the homologous of the two enzymes eukaryotic a3CRPB2 RPB3 RPB1 RPB11 RPB6 15
15 a a b’ w RPB3 RPB11 RPB2 RPB1 RPB6 Fig 12-2 RNAP Comparison The same color indicate the homologous of the two enzymes prokaryotic eukaryotic b