What is the significance of the promoter and terminator regions of the DNA?
Those proteins are the worker molecules that do the jobs necessary to contract your muscles or let your eye detect light. The promoter and terminator regions of DNA are there to make sure the right proteins are built in the right place and at the right time.
Does sigma70 have a consensus sequence?
Genes recognized by σ70 all contain similar promoter consensus sequences consisting of two parts. Relative to the DNA base corresponding to the start of the RNA transcript, the consensus promoter sequences are characteristically centered at 10 and 35 nucleotides before the start of transcription (−10 and −35).
Where on the DNA strand does RNA polymerase bind to start transcription?
the promoter
To begin transcribing a gene, RNA polymerase binds to the DNA of the gene at a region called the promoter. Basically, the promoter tells the polymerase where to “sit down” on the DNA and begin transcribing.
What is the function of the promoter?
Promoters are DNA sequences whose purpose is not to encode information about the organism itself, but rather they serve as a kind of “On” switch to initiate the biological process of transcription for the genes which follow the promoter DNA sequence.
What is the difference between promoter and terminator?
A promoter is a region of DNA where RNA polymerase binds to initiate transcription. A terminator is a sequence of DNA that causes RNA polymerase to terminate transcription.
What is the TATA box MCAT?
The TATA box is the binding site for a transcription factor called TATA-binding protein (TBP). Several additional transcription factors and RNA polymerase combine around the TATA box to form the pre-initiation complex.
How do promoters and terminators work?
Promoters and terminators are stretches of DNA upstream and downstream (respectively) of genes that control both the rate at which the gene is transcribed and the rate at which mRNA is degraded. As a result, both of these elements control net protein expression from a synthetic construct.
Can we predict sigma54-dependent promoters based on target sequences?
We have developed an improved method for the prediction of sigma54-dependent promoters which combines the scores of sigma54-RNAP target sequences and those of activator binding sites.
What is the sigma54 class of sigma factors?
The sigma54 class of sigma factors has traditionally been divided into three regions with the N-terminal ~60 residues termed Region I, followed by a linker domain termed Region II, and a large C-terminal region with multiple individually folding functional domains (from ~69 to 398 in A. aeolicus) termed Region III. [4]
How does the sigma54-rnap holoenzyme assembles on a conserved promoter sequence?
The sigma54-RNAP holoenzyme assembles on a conserved promoter sequence at the -24 site through specific interactions with its C-terminal RpoN box motif. This is shown below for Aquifex aeolicus sigma54 and the gene nirB (and discussed in more detail in the -24 DBD section further down).
What is the mechanism of transcription for sigma54?
sigma54 is unique among the bacterial sigma factors. Besides not being related in sequence with the rest of such factors, its mechanism of transcription initiation is completely different and requires the participation of a transcription activator.
