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Translation promotes transcription elongation and regulates transcription termination. Functional coupling between transcription and translation is caused by direct physical interactions between the ribosome and RNA polymerase ("expressome complex"), ribosome-dependent changes to nascent mRNA secondary structure which affect RNA polymerase activity (e.g. "attenuation"), and ribosome-dependent ...
The hybridization of strands 1 and 2 to form the 1–2 structure prevents the formation of the 2–3 structure, while the formation of 2-3 prevents the formation of 3–4. The 3–4 structure is a transcription termination sequence, once it forms RNA polymerase will disassociate from the DNA and transcription of the structural genes of the ...
DNA polymerase II (also known as DNA Pol II or Pol II) is a prokaryotic DNA-dependent DNA polymerase encoded by the PolB gene. [1] DNA Polymerase II is an 89.9-kDa protein and is a member of the B family of DNA polymerases. It was originally isolated by Thomas Kornberg in 1970, and characterized over the next few years.
A eukaryotic cell has a nucleus that separates the processes of transcription and translation. Eukaryotic transcription occurs within the nucleus where DNA is packaged into nucleosomes and higher order chromatin structures. The complexity of the eukaryotic genome necessitates a great variety and complexity of gene expression control.
The hallmark difference of elongation in eukaryotes in comparison to prokaryotes is its separation from transcription. While prokaryotes are able to undergo both cellular processes simultaneously, the spatial separation that is provided by the nuclear membrane prevents this coupling in eukaryotes.
Transcriptional modification or co-transcriptional modification is a set of biological processes common to most eukaryotic cells by which an RNA primary transcript is chemically altered following transcription from a gene to produce a mature, functional RNA molecule that can then leave the nucleus and perform any of a variety of different functions in the cell. [1]
Mediator has been shown to make contacts with the polymerase in the transcription preinitiation complex. [3] A recent model showing the association of the polymerase with mediator in the absence of DNA is shown in the figure to the left. [4] In addition to RNA polymerase II, mediator must also associate with transcription factors and DNA.
Initiation of translation in bacteria involves the assembly of the components of the translation system, which are: the two ribosomal subunits (50S and 30S subunits); the mature mRNA to be translated; the tRNA charged with N-formylmethionine (the first amino acid in the nascent peptide); guanosine triphosphate (GTP) as a source of energy, and the three prokaryotic initiation factors IF1, IF2 ...