武汉大学生命科学学院：《分子生物学》（英文版）Part III：Expression of the Genome CHAPTER12 Mechanisms of Transcription

Molecular biology of the Gene 5/E - Watson et al. ( 2004) Part l: Chemistry and Genetics Part Maintenance of the Genome Part l: Expression of the Genome Part IV: Regulation Part va methods 刻博来字 Wuhan Univ

2 Molecular Biology of the Gene, 5/E --- Watson et al. (2004) Part I: Chemistry and Genetics Part II: Maintenance of the Genome Part III: Expression of the Genome Part IV: Regulation Part V: Methods

Part l: Expression of the genome Ch 12: Mechanisms of transcription Ch 13: RNA splicing Ch 14: Translation Ch 15: The genetic code

3 Ch 12: Mechanisms of transcription Ch 13: RNA splicing Ch 14: Translation Ch 15: The genetic code Part III: Expression of the Genome

Molecular Biology course Chapter 12: Mechanisms of Transcription 1. RNA polymerase and transcription cycle WATSON 2. The transcription cycle in bacteria GANN LEVINE LOSICK 3. Transcription in eukaryotes

Chapter 12: Mechanisms of Transcription 1. RNA polymerase and transcription cycle 2. The transcription cycle in bacteria 3. Transcription in eukaryotes •Molecular Biology Course

The Central Dogma Transcription Translation DNA RNAPROTEIN replication

5 The Central Dogma DNA RNA PROTEIN Transcription Translation replication

Transcription is very similar to DNA replication but there are some important differencesi 1, RNA is made of ribonucleotides 2. RNa polymerase catalyzes the reaction 3. The synthesized rNA does not remain base-paired to the template DNA strand 4. Less accurate (error rate: 10-4)

6 Transcription is very similar to DNA replication but there are some important differences: 1.RNA is made of ribonucleotides 2.RNA polymerase catalyzes the reaction 3.The synthesized RNA does not remain base-paired to the template DNA strand 4.Less accurate (error rate: 10-4)

5. Transcription selectively copies only certain parts of the genome and makes one to several hundred, or even thousand copies of any given section of the genome(Replication?)

7 5.Transcription selectively copies only certain parts of the genome and makes one to several hundred, or even thousand, copies of any given section of the genome. (Replication?)

DNA duplex m RNA Transcription bubble Fig 12-1 Transcription of DNA into RNA

8 Fig 12-1 Transcription of DNA into RNA Transcription bubble

C9HAPTER12: Mechanisms of transcription Topic 1: RNA Polymerase and The Transcription Cycle See the interactive animation 刻博来字 Wuhan Universit

9 Topic 1: RNA Polymerase and The Transcription Cycle CHAPTER12: Mechanisms of Transcription See the interactive animation

RNA polymerases come in s different forms but share many features a- RNA polymerases performs essentially the same reaction in all cells a- Bacteria have only a single e. RNA polymerases while in eukaryotic cells there are 9 three: RNA Pol I, II and III 10

10 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 RNA Pol II transcribe tRNA gene some small nuclear RNA genes and the 5s rRNA genes

11 ◼ 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 II transcribe tRNA gene, some small nuclear RNA genes and the 5S rRNA genes