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In genetics, a transcription terminator is a section of nucleic acid sequence that marks the end of a gene or operon in genomic DNA during transcription.This sequence mediates transcriptional termination by providing signals in the newly synthesized transcript RNA that trigger processes which release the transcript RNA from the transcriptional complex.
Termination signals bring a stop to transcription, ensuring that only gene-encoding parts of the chromosome are transcribed. [1] Transcription begins at the promoter when RNA polymerase , an enzyme that facilitates transcription of DNA into mRNA, binds to a promoter , unwinds the helical structure of the DNA, and uses the single-stranded DNA as ...
In order for proper gene expression to occur, transcription must stop at specific sites. Two termination mechanisms are well known: Intrinsic termination (also called Rho-independent termination): Specific DNA nucleotide sequences signal the RNA polymerase to stop.
In terms of transcription termination, the archaeal genome is unique in that it is sensitive to both intrinsic termination and factor-dependent termination. Bioinformatic analysis has shown that approximately half of the genes and operons in Archaea arrange themselves into signals or contain signals for intrinsic termination. [ 10 ]
Transcription is the process of copying a segment of DNA into RNA for the purpose of gene expression. Some segments of DNA are transcribed into RNA molecules that can ...
The transcription termination site is located after the ORF, beyond the translation stop codon. If transcription were to cease before the stop codon, an incomplete protein would be made during translation.
Stop codon suppression or translational readthrough occurs when in translation a stop codon is interpreted as a sense codon, that is, when a (standard) amino acid is 'encoded' by the stop codon. Mutated tRNAs can be the cause of readthrough, but also certain nucleotide motifs close to the stop codon.
Ribosome-mediated attenuation of the trp operon relies on the fact that, in bacteria, transcription and translation proceed simultaneously. Attenuation involves a provisional stop signal (attenuator), located in the DNA segment that corresponds to the leader sequence of mRNA.