What is eukaryotic transcriptional control?
Transcriptional control is the primary means of regulating gene expression in eukaryotes, as it is in bacteria. In eukaryotic genomes, cis-acting control elements that regulate transcription from a promoter often are located many kilobases away from the start site.
What are the stages of transcriptional control?
First, transcription is controlled by limiting the amount of mRNA that is produced from a particular gene. The second level of control is through post-transcriptional events that regulate the translation of mRNA into proteins. Even after a protein is made, post-translational modifications can affect its activity.
What are the types of transcriptional control?
Some post-translational modifications known to regulate the functional state of transcription factors are phosphorylation, acetylation, SUMOylation and ubiquitylation. Transcription factors can be divided in two main categories: activators and repressors.
What is involved in post transcriptional control?
Posttranscriptional regulation includes alternative splicing (which determines the translated mRNA sequence itself), stability of the mRNA strand (which can be actively degraded in a regulated manner), transport of the mRNA to the ribosome, and binding of mRNA to the ribosome.
What is involved in post-transcriptional control?
What are transcription factors and give an account of control of transcription in eukaryotes?
In eukaryotes, an important class of transcription factors called general transcription factors (GTFs) are necessary for transcription to occur. Many of these GTFs do not actually bind DNA, but rather are part of the large transcription preinitiation complex that interacts with RNA polymerase directly.
Where does post-transcriptional control occur?
Post-transcriptional control can occur at any stage after transcription, including RNA splicing, nuclear shuttling, and RNA stability. Once RNA is transcribed, it must be processed to create a mature RNA that is ready to be translated. This involves the removal of introns that do not code for protein.
Which method is utilized by eukaryotes to control their gene?
Gene expression in eukaryotic cells is regulated by repressors as well as by transcriptional activators. Like their prokaryotic counterparts, eukaryotic repressors bind to specific DNA sequences and inhibit transcription.
Where do transcriptional regulators most commonly bind to?
Some transcription factors bind to a DNA promoter sequence near the transcription start site and help form the transcription initiation complex. Other transcription factors bind to regulatory sequences, such as enhancer sequences, and can either stimulate or repress transcription of the related gene.
What are the three levels of transcription in eukaryotes?
Eukaryotes show three levels of transcriptional regulation 1 – Chromatin structure in gene regulation 2 – RNA and transcriptional modulation of gene expression 3 – Transcription factors regulating gene expression Advances in PMB 2012 Chromatin structure in gene regulation
How is the expression of genes controlled in eukaryotes?
Although the control of geneexpression is far more complex in eukaryotes than in bacteria, the same basic principles apply. The expression of eukaryotic genes is controlled primarily at the level of initiation of transcription, although in some cases transcription may be attenuated and regulated at subsequent steps.
What is the role of repressors in the regulation of transcription?
The regulation of transcription by repressors as well as by activators considerably extends the range of mechanisms that control the expression of eukaryotic genes. One important role of repressors may be to inhibit the expression of tissue-specific genes in inappropriate cell types.
How is the transcription of genes in bacteria regulated?
As already discussed, transcription in bacteria is regulated by the binding of proteins to cis-acting sequences (e.g., the lac operator) that control the transcription of adjacent genes.