What is the T7 promoter sequence?

What Is the T7 Promoter Sequence? The T7 promoter is a sequence of DNA 18 base pairs long up to transcription start site at +1 (5′ – TAATACGACTCACTATAG – 3′) that is recognized by T7 RNA polymerase1 .

What does T7 promoter do?

T7 RNA polymerase is a very active enzyme: it synthesizes RNA at a rate several times that of E. coli RNA polymerase and it terminates transcription less frequently; in fact, its transcription can circumnavigate a plasmid, resulting in RNA several times the plasmid length in size.

What polymerase is recruited to T7 class I genes?

T7 RNA polymerase (T7 RNAP) recognizes specific promoter DNA sequences, which have to be double-stranded and transcribes only DNA downstream from a T7 promoter.

Is T7 a strong promoter?

T7 RNA polymerase is very selective and efficient, resulting both in a high frequency of transcription initiation and effective elongation. These features result in an RNA elongation that is approximately five-fold faster than for E. coli RNA polymerase; hence, the T7 promoter is a much stronger promoter than the E.

What is the T7 expression system?

The T7 expression system allows high-level expression from the strong bacteriophage T7 promoter. It’s ideal for expressing soluble, nontoxic recombinant proteins in E. coli. The T7 expression vectors are designed to facilitate cloning using Gateway® technology, and easy protein purification and detection.

Is T7 promoter a protein?

The most widespread, efficient prokaryotic protein-producing system is one where the T7 phage polymerase recognizes the T7 phage promoter (T7 p/p system). Unfortunately, in this system, target protein expression gradually declines and is often undetectable following 3 to 5 subcultures.

Does T7 virus have a vaccine?

T7 phage may be potentially useful as a delivery vector for DNA vaccine transfer. The surface display capability of T7 phage also enlarge the use in vaccine design, for it can surface display antigen epitope and carry DNA vaccine within one particles.

What is the origin of T7 polymerase?

Bacteriophage T7 DNA replication is initiated at a site 15% of the distance from the genetic left end of the chromosome. This primary origin contains two tandem T7 RNA polymerase promoters (phi 1.1A and phi 1.1B) followed by an A + T-rich region.

How are T7 genes transcribed?

Bacteriophage T7 relies on its own RNA polymerase (RNAp) to transcribe its middle and late genes. Early genes, which include the viral RNAp gene, are transcribed by the host RNAp from three closely spaced strong promoters — A1, A2, and A3. One middle T7 gene product, gp2, is a strong inhibitor of the host RNAp.

Is the T7 promoter constitutive?

These promoters are recognized by the T7 RNA Polymerase and are constitutive meaning that their activity is dependent on the availability of RNA polymerase, but is not affected by any transcription factors.

What is T7 in biology?

Bacteriophage T7 (or the T7 phage) is a bacteriophage, a virus that infects bacteria. It infects most strains of Escherichia coli and relies on these hosts to propagate. Bacteriophage T7 has a lytic life cycle, meaning that it destroys the cell it infects.