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Bacteria have a σ-factor that detects and binds to promoter sites but eukaryotes do not need a σ-factor. Instead, eukaryotes have transcription factors that allow the recognition and binding of promoter sites. [2] Overall, transcription within bacteria is a highly regulated process that is controlled by the integration of many signals at a ...
Transcription factors are essential for the regulation of gene expression and are, as a consequence, found in all living organisms. The number of transcription factors found within an organism increases with genome size, and larger genomes tend to have more transcription factors per gene. [14]
Several cell function specific transcription factors (there are about 1,600 transcription factors in a human cell [14]) generally bind to specific motifs on an enhancer [15] and a small combination of these enhancer-bound transcription factors, when brought close to a promoter by a DNA loop, govern level of transcription of the target gene.
A transcription factor is a protein that binds to specific DNA sequences (enhancer or promoter), either alone or with other proteins in a complex, to control the rate of transcription of genetic information from DNA to messenger RNA by promoting (serving as an activator) or blocking (serving as a repressor) the recruitment of RNA polymerase.
Using the enzyme helicase, RNAP locally opens the double-stranded DNA so that one strand of the exposed nucleotides can be used as a template for the synthesis of RNA, a process called transcription. A transcription factor and its associated transcription mediator complex must be attached to a DNA binding site called a promoter region before ...
A sigma factor (σ factor or specificity factor) is a protein needed for initiation of transcription in bacteria. [1] [2] It is a bacterial transcription initiation factor that enables specific binding of RNA polymerase (RNAP) to gene promoters. It is homologous to archaeal transcription factor B and to eukaryotic factor TFIIB. [3]
Free-living bacteria have the largest genomes out of the three types of bacteria; however, they have fewer pseudogenes than bacteria that have recently acquired pathogenicity. Facultative and recently evolved pathogenic bacteria exhibit a smaller genome size than free-living bacteria, yet they have more pseudogenes than any other form of bacteria.
However, some bacteria have protein-bound organelles in the cytoplasm which compartmentalise aspects of bacterial metabolism, [62] [63] such as the carboxysome. [64] Additionally, bacteria have a multi-component cytoskeleton to control the localisation of proteins and nucleic acids within the cell, and to manage the process of cell division ...