In the prokaryotes, there is a unit of genes known as an operon. An operon is actually a set of genes which gives rise to multiple proteins. It is here at the operon that the transcription of the prokaryotes is regulated. The proteins which actually bind to the operon and the site of this binding determine whether there will be an up-regulation or a down-regulation of the transcription process. There are two types of proteins which are involved in this regulation. They are either repressors or activators. Repressors attach the operator which is a region present on the promoter.
This binding prevents the binding of the enzyme RNA polymerase to the DNA strand. Hence there is an inhibition in the process of transcription. On the other hand, proteins which facilitate the binding of RNA polymerase are activators. T5hese activator proteins bind to -35 region that is present in the flanking region or even further ahead enhancing the process of transcription. Prokaryotic transcription begins with the unwinding of the double-stranded SNA. This unwinding is induced by the binding of RNA polymerase to the promoter area.
The sigma factor comes into play when the RNA transcript has ten nucleotide bases. The transcription only stops after a termination signal is encountered by the RNA polymerase. The prokaryotic transcript is a polycistronic transcript. A polycistronic transcript is one which on being translated gives a great number of different proteins. The process of transcription is a complex process and the regulation of it has been presented. In the prokaryotes, there are other two regulatory mechanisms which can further explain the control of in these prokaryotic organisms.
These two mechanisms are termed as positive control and negative control. The functioning of these control mechanisms will be considered with examples. An operon which is a genetic unit that consists of genes that produce a number of genes works in the control of prokaryotic transcription. The operon codes for a polycistronic transcript which codes for multiple proteins. These proteins may be enzymes which function in collaboration.
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