In prokaryotes, the type of regulation that targets mature mRNA before it can be used in protein synthesis primarily involves ** RNA degradation (or mRNA decay)**. This regulation can occur through several mechanisms, including:
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Endonucleolytic cleavage: Specific endonucleases can cleave the mRNA into smaller fragments, leading to its degradation.
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Exonucleolytic degradation: 3' to 5' exonucleases, such as the exosome complex or RNase R, can degrade the mRNA from the ends after it has been stabilized less, leading to decreased translation.
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sRNA interaction: Small regulatory RNAs (sRNAs) can bind to target mRNAs, sometimes blocking ribosome binding sites or promoting degradation by recruiting ribonucleases.
These mechanisms ensure that mRNA levels are appropriately controlled, affecting gene expression and protein synthesis in response to various cellular conditions.