A riboswitch is an RNA sequence located in the 5′ untranslated region of mRNA that regulates gene expression by binding small molecules. It consists of an aptamer domain that binds the ligand and an expression platform that forms secondary structures to control transcription or translation, often by halting transcription or blocking the ribosome binding site in prokaryotes.
Where in the mRNA are riboswitches typically located?
Riboswitches are typically found in the 5′ untranslated region (UTR) of mRNA.
What are the two main domains of a riboswitch and their functions?
The aptamer domain binds the small molecule ligand, while the expression platform forms secondary structures to regulate gene expression.
How can riboswitches affect transcription in prokaryotes?
Riboswitches can form terminator structures that halt transcription by causing RNA polymerase to stop.
What is the role of the terminator structure in riboswitch function?
The terminator structure can either terminate transcription or block the ribosome binding site to prevent translation.
Why can riboswitches regulate both transcription and translation in prokaryotes?
In prokaryotes, transcription and translation occur in the same compartment, allowing riboswitches to influence both processes.
What does the aptamer domain of a riboswitch specifically bind?
The aptamer domain binds small molecules, such as chemicals or metabolites.
How do riboswitches control the expression of the mRNA they are part of?
By binding ligands and forming secondary structures, riboswitches regulate the expression of their own mRNA.
What do the letters like W, K, D, and Y represent in riboswitch RNA sequences?
These letters are codes for different possible RNA nucleotides at those positions, indicating nucleotide variability.
What type of gene regulation do riboswitches exemplify?