- 15.1: Introduction
- Transcription, the synthesis of RNA based on a DNA template, is the central step of the Central Dogma proposed by Crick in 1958. The basic steps of transcription are the same as for replication: initiation, elongation and termination. Differences between transcription in prokaryotes and eukaryotes are in the details.
- 15.2: Overview of Transcription
- All cells make three main kinds of RNA: ribosomal RNA (rRNA), transfer RNA (tRNA) and messenger RNA (mRNA). rRNA is a structural as well as enzymatic component of ribosomes, the protein-synthesizing machine in the cell. Quantitatively, rRNAs are by far the most abundant RNAs in the cell and mRNAs, the least. Three rRNAs and about 50 ribosomal proteins make up the two subunits of a bacterial ribosome, as illustrated below.
- 15.3: Details of Transcription
- Some proteins bind DNA to regulate transcription, inducing or silencing transcription of a gene. We will discuss their role in the regulation of gene expression later. Other proteins interact with DNA simply to allow transcription. These include one or more that, along with RNA polymerase itself, that must bind to the gene promoter to initiate transcription.
Thumbnail: Simplified diagram of mRNA synthesis and processing. (CC BY 3.0 - unported ; Kelvinsong).