6 Questions
What is the main function of microRNAs in eukaryotes?
To regulate gene expression at the post-transcriptional level
What is the role of the 7-methylguanosine cap in mRNA capping?
To recruit the ribosome to initiate translation
What is the function of polyadenylation in eukaryotes?
To add a poly(A) tail to the 3' end of mRNA
How do RNA-binding proteins regulate translation?
All of the above
What is the function of the protein HuR?
To stabilize mRNA
What is the result of miRNA-mRNA binding?
Inhibition of translation initiation
Study Notes
Translation Regulation in Eukaryotes
MicroRNA-mediated Regulation
- MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression at the post-transcriptional level
- miRNAs bind to messenger RNA (mRNA) and prevent its translation or induce its degradation
- miRNAs recognize specific mRNA targets through complementary base pairing
- Regulation of miRNA-mediated translation:
- miRNA-mRNA binding leads to inhibition of translation initiation
- miRNA-mRNA binding can also induce deadenylation and decapping of mRNA, leading to its degradation
MRNA Capping
- mRNA capping is the process of adding a 7-methylguanosine (m7G) cap to the 5' end of mRNA
- The cap is recognized by the eukaryotic translation initiation factor 4E (eIF4E)
- Capping is essential for:
- Translation initiation: the cap recruits eIF4E, which interacts with the ribosome to initiate translation
- mRNA stability: the cap protects the mRNA from degradation by exonucleases
Polyadenylation
- Polyadenylation is the process of adding a poly(A) tail to the 3' end of mRNA
- The poly(A) tail is recognized by the poly(A)-binding protein (PABP)
- Polyadenylation is essential for:
- Translation initiation: PABP interacts with eIF4G, which recruits the ribosome to initiate translation
- mRNA stability: the poly(A) tail protects the mRNA from degradation by exonucleases
RNA-binding Proteins
- RNA-binding proteins (RBPs) are proteins that bind to specific mRNA sequences or structures
- RBPs can regulate translation by:
- Blocking or masking the mRNA 5' cap or 3' poly(A) tail
- Recruiting or inhibiting translation initiation factors
- Modulating mRNA localization and stability
- Examples of RBPs:
- HuR: stabilizes mRNA by binding to the 3' UTR
- AU-binding proteins: bind to AU-rich elements in the 3' UTR and regulate mRNA stability and translation
MicroRNA-mediated Regulation
- MicroRNAs (miRNAs) regulate gene expression at the post-transcriptional level by binding to messenger RNA (mRNA) and preventing its translation or inducing its degradation
- miRNAs recognize specific mRNA targets through complementary base pairing
- miRNA-mRNA binding leads to inhibition of translation initiation
- miRNA-mRNA binding can also induce deadenylation and decapping of mRNA, leading to its degradation
mRNA Capping
- mRNA capping is the process of adding a 7-methylguanosine (m7G) cap to the 5' end of mRNA
- The cap is recognized by the eukaryotic translation initiation factor 4E (eIF4E)
- Capping is essential for translation initiation, as the cap recruits eIF4E, which interacts with the ribosome to initiate translation
- Capping is essential for mRNA stability, as the cap protects the mRNA from degradation by exonucleases
Polyadenylation
- Polyadenylation is the process of adding a poly(A) tail to the 3' end of mRNA
- The poly(A) tail is recognized by the poly(A)-binding protein (PABP)
- Polyadenylation is essential for translation initiation, as PABP interacts with eIF4G, which recruits the ribosome to initiate translation
- Polyadenylation is essential for mRNA stability, as the poly(A) tail protects the mRNA from degradation by exonucleases
RNA-binding Proteins
- RNA-binding proteins (RBPs) are proteins that bind to specific mRNA sequences or structures
- RBPs can regulate translation by blocking or masking the mRNA 5' cap or 3' poly(A) tail
- RBPs can regulate translation by recruiting or inhibiting translation initiation factors
- RBPs can regulate translation by modulating mRNA localization and stability
- Examples of RBPs:
- HuR: stabilizes mRNA by binding to the 3' UTR
- AU-binding proteins: bind to AU-rich elements in the 3' UTR and regulate mRNA stability and translation
This quiz covers the role of microRNAs in regulating gene expression at the post-transcriptional level, including their binding to mRNA and prevention of translation or degradation.
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