Transcription

Introduction
Transcription is simply the synthesis of RNA from DNA template. It is also important
is the concept that transcription, prokaryotic or eukaryotic, there are three main events.
Opening - the binding of RNA polymerase DNA double-hard, which is a step
Strandedness transition to a unique alliance of the region, RNA polymerase binds in a series of
DNA called the promoter. Initiation is the most important step in gene expression!

Elongation - the covalent addition of nucleotides to the 3 'end of the growing polynucleotide
chain, which includes development of a short stretch of DNA is a difficult one short
Termination - the recognition sequence of transcription termination and release of
RNA polymerase

Although transcription is performed by the enzyme RNA polymerase needs of other proteins to produce a copy. These factors are associated with RNA polymerase directly or construction of real transcription apparatus. General term for this type of protein is associated transcription factor.
Transcription factor - any protein that RNA polymerase is required for transcription

Role of transcription factors
associated with RNA polymerase
to bind to another transcription factor
bind to cis-DNA sequences that act
RNA polymerase and the group of proteins that come into direct contact with him, is called the basal transcription apparatus. This is a machine that is directly responsible for transcription.
Basal transcription apparatus - RNA polymerase + common factors as necessary to initiate transcription
Other factors that interact directly or via the coactivator proteins with the basal transcription apparatus are also important for transcription. They usually have a positive effect on transcription, but sometimes it can suppress gene expression through transcripion. These factors are called upstream factors.
Factors, Upstream - Ubiquitous factors that increase the efficiency of transcription initiation, a complex of factors unique to each promoter
Functions of the upstream factors
influence the initiation of transcription in contact with members of the basal apparatus
encourage installation of equipment
coactivators can be connected to interact with the basal apparatus
usually associated with TFIID, TFIIB or TFIIE
TAF provides different TFIID may interact with, if TAF are unique to a particular organizer accelerator capable of controlling the interaction of specific transcription
most interactions are positive in nature and induce transcription
repressors may prevent the development of basal apparatus
Finally, some factors that are temporary or space, or directly in response to the environment.These factors are the final piece in controlling gene expression. They are called inducible factors.
Inducible factors - operate in the same way as most factor but its synthesis is regulated by time or space
Given all the discussion of the basal transcription apparatus and induction factors up and we can learn to achieve the definition of promoter. The definition reflects the interaction of all the important proteins and DNA, which are linked together.
Organizer - all the DNA sequences containing binding sites for RNA polymerase and factors, transcription required for normal transcription