miRNAs target endogenous mRNAs in a sequence-specific manner. Explain, conceptually, how one might identify potential mRNA targets for a given miRNA if you only know the sequence of the miRNA and the sequence of all mRNAs in a cell or tissue of interest.
Ch. 18 - Post-transcriptional Regulation in Eukaryotes

Chapter 18, Problem 17
While circular RNAs were first described long ago, they have only recently been investigated for function. What are their known and suspected functions in the cell?
Verified step by step guidance1
Understand that circular RNAs (circRNAs) are a type of non-coding RNA characterized by a covalently closed loop structure without 5' caps or 3' poly-A tails, which makes them resistant to exonucleases and more stable than linear RNAs.
Explore the known functions of circRNAs, such as acting as microRNA (miRNA) sponges, where they bind and sequester miRNAs, preventing these miRNAs from downregulating their target messenger RNAs (mRNAs).
Consider their role in regulating transcription and splicing by interacting with RNA-binding proteins or influencing the expression of their parental genes.
Investigate the suspected functions, including their potential involvement in protein translation, as some circRNAs have been found to contain internal ribosome entry sites (IRES) that may allow them to be translated into peptides.
Recognize the emerging evidence that circRNAs may play roles in cellular stress responses, development, and disease processes such as cancer, highlighting the importance of ongoing research to fully elucidate their functions.

Verified video answer for a similar problem:
This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
2mWas this helpful?
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Circular RNA Structure and Biogenesis
Circular RNAs (circRNAs) are a type of non-coding RNA characterized by a covalently closed loop structure without 5' or 3' ends. They are generated mainly through back-splicing events where a downstream splice donor joins an upstream splice acceptor, distinguishing them from linear RNAs.
Recommended video:
Functions of Circular RNAs
CircRNAs are known to regulate gene expression by acting as microRNA sponges, binding and sequestering microRNAs to prevent them from repressing target mRNAs. They may also interact with RNA-binding proteins and influence transcription or splicing, and some circRNAs can be translated into peptides.
Recommended video:
Biological Significance and Potential Roles
CircRNAs are implicated in various cellular processes including development, differentiation, and disease states like cancer and neurological disorders. Their stability and abundance suggest roles in post-transcriptional regulation and cellular signaling, though many functions remain under investigation.
Recommended video:
Guided course
Overview
Related Practice
Textbook Question
745
views
Textbook Question
In principle, RNAi may be used to fight viral infection. How might this work?
544
views
Textbook Question
Competing endogenous RNAs act as molecular 'sponges.' What does this mean, and what do they compete with?
563
views
Textbook Question
How are mRNAs stored within the cell in a translationally inactive state, and how can their translation be stimulated?
555
views
Textbook Question
How and why are eukaryotic mRNAs transported and localized to discrete regions of the cell?
462
views
Textbook Question
How is it possible that a given mRNA in a cell is found throughout the cytoplasm but the protein that it encodes is only found in a few specific regions?
437
views
