BI - Promoter Elements

Questions

What are Promoter Elements?
- Promoter elements are DNA sequences that are located upstream of a gene's transcription start site and are recognized by proteins called transcription factors.
  These elements are essential for the initiation of transcription, which is the process of synthesizing an RNA molecule from a DNA template.
- ==Promoter elements typically include the core promoter and regulatory elements==.
  - The core promoter is the region immediately upstream of the transcription start site and contains DNA sequences that are recognized by RNA polymerase and its associated factors, which are required for the initiation of transcription.
  - Regulatory elements, on the other hand, are DNA sequences that are located further upstream of the core promoter and can affect the activity of the core promoter and/or the efficiency of transcription initiation.
- There are several types of regulatory elements found in promoter regions, including enhancers, silencers, and response elements.
  - Enhancers are DNA sequences that can increase the activity of the core promoter, leading to increased transcriptional activity.
  - Silencers, on the other hand, are DNA sequences that can decrease the activity of the core promoter, leading to decreased transcriptional activity.
  - Response elements are DNA sequences that are recognized by specific transcription factors that are activated in response to external signals or stimuli, allowing for rapid changes in gene expression in response to environmental cues.
- The precise sequence and arrangement of promoter elements can vary widely between genes, contributing to the complexity and diversity of gene expression in eukaryotic organisms.
  Understanding the function and regulation of promoter elements is crucial for understanding how genes are expressed and regulated, with important implications for fields such as medicine and biotechnology.

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IMPORTANTE

IMPORTANTE RNA Polymerase is the protein responsabile of TRANSCRIPTING DNA into RNA (that will be than TRADUCED into a chain of amminoacids: a protein) #IMPORTANTE The PROKARYOTIC RNA Polymerase is an assemblies of a set of different protein subunits each of which has an important and specific role: #IMPORTANTE The $β ’$ , $β$ , and $α$ protein subunits are well preserved from an evolutional point of view, while the $σ$ subunit is less conserved and tend to be less conserved, and several variants have been detected in the same organism. #IMPORTANTE The variaty of the $σ$ subunit is what allows for the organism to have different response to different stimuli: Where the Sequence -35 and Sequence -10 are the different promotor regions before an open reading frame

IMPORTANTE The promoter element is the DNA colored in green)

The promoter element is the region of DNA where the RNA Polymerase will bind and start transcripting:

Promoters element could be upstream or downstream with respect to the translation site: (In red the start of the transcription site, the actual “protein code”)

Famous transcription site (upstream ones) are the BRE Element and the TATA Box A downstream famous promoter element is the DPE (Downstream Promoter Element)

To classify if the promoter is weak or strong we can use an in vivo test, attaching the promoter to an easily recognizible gene, called a “reporter” that when transripted will create a fluoroescent protein: If the flouroescence intensity is high the promoter is strong, otherwise is weak:

Also a promoter can be helped by a nerby sequence, an enhancer which can influence the promoter, augmentic it’s effect, instead a repressor can reduce the promoter transcription effect: Online Resource: Youtube

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Slides with Notes

IMPORTANTE RNA Polymerase is the protein responsabile of TRANSCRIPTING DNA into RNA (that will be than TRADUCED into a chain of amminoacids: a protein) #IMPORTANTE The PROKARYOTIC RNA Polymerase is an assemblies of a set of different protein subunits each of which has an important and specific role: #IMPORTANTE The $β ’$ , $β$ , and $α$ protein subunits are well preserved from an evolutional point of view, while the $σ$ subunit is less conserved and tend to be less conserved, and several variants have been detected in the same organism. #IMPORTANTE The variaty of the $σ$ subunit is what allows for the organism to have different response to different stimuli: Where the Sequence -35 and Sequence -10 are the different promor regions before an open reading frame