Eukaryotic Transcription

Complexity of transcription - Transcription in eukaryotes is a much more complex process than in prokaryotes. Not only is there much more discrimination in what is to be transcribed and what is not, but transcription is precisely programmed during development and tissue differentiation. Furthermore, the transcription machinery must deal with the complicated levels of structure in eukaryotic chromatin.

Proteins - Eukaryotic cells have several different RNA polymerases, each with a specialized function (Table 28.3). In addition to the special RNA polymerases that function in mitochondria and chloroplasts, there are three enzymes that transcribe various portions of the nuclear genome. Each of the nuclear RNA polymerases contains about a dozen subunits. In contrast to prokayotic systems, all of the eukaryotic RNA polymerases require additional protein factors (transcription factors) in order to bind to a promoter and initiate transcription. Transcription factors seem to play a major role in determining selectivity in the transcription of genes.

See also: RNA Polymerase I Transcription, RNA Polymerase III Transcription, RNA Polymerase II Transcription, Chromatin Structure and Transcription, Eukaryotic Transcription, Termination of Eukaryotic Transcription, Chromatin Remodeling, Transcription Factor Binding Domains

INTERNET LINKS:

> 1. Transcription

> 2. Eukaryotic Promoter Database

> 3. Eukaryotic Transcription