22 Questions
What is the function of the 7-methylguanosine cap at the 5’end of eukaryotic mRNAs?
Enhancing mRNA translation
What is the role of snRNAs in splicing mechanisms?
Guiding the splicing of pre-mRNAs
How can alternative splicing be regulated?
By regulating the activity of splicing factors
What is the physiological importance of alternative polyadenylation site selection?
Regulation of mRNA stability
What is the purpose of 5' cap formation in eukaryotic mRNAs?
All of the above
Which molecule achieves specificity through base-pairing with pre-mRNA splice sites during splicing?
snRNAs
What is the function of the spliceosome in pre-mRNA splicing?
Mediates pre-mRNA splicing
Which type of gene processing generates multiple mRNA isoforms from a single gene?
Alternative splicing
What is the main role of the carboxy-terminal domain (CTD) of RNA polymerase II in recruiting RNA processing factors?
Phosphorylation
How are bacterial and eukaryotic mRNA molecules different in structure?
Differences in 5' UTR and 3' UTRs
What is the process of removing introns from the pre-mRNA called?
Splicing
'Drosophila's DSCAM gene can potentially produce over how many isoforms through alternative splicing?
38,000
Which of the following is NOT a function of the poly(A) tail in eukaryotes?
Facilitates splicing of pre-mRNAs
Intron retention due to missplicing can lead to which of the following human diseases?
Myotonic dystrophy
Which protein complex is involved in the cleavage and polyadenylation at the 3’ end of eukaryotic pre-mRNAs?
CPSF and CFs
What is the primary role of mRNP exporters in eukaryotic cells?
Ensuring directional export of mRNAs from nucleus to cytoplasm
Which genetic mutation can lead to ß-thalassemia, an inherited blood disorder?
Mutation of splice sites in the ß-globin gene (HBB)
What can lead to different transcript variants in certain tissues/cells in eukaryotes?
Alternative splicing patterns
Which factor is responsible for binding to the AAUAAA sequence during cleavage and polyadenylation at the 3’ end of eukaryotic pre-mRNAs?
CPSF
What kind of mutations can cause Myotonic dystrophy, a neuromuscular disease?
Mutations in splicing factors
Which process involves capture of polyadenylated RNAs (mRNAs) by hybridization to oligo-(dT) coupled magnetic beads?
Isolation of mRNAs
Which modification occurs to residue 1 during addition of the 5’ cap to mRNA in eukaryotic cells?
Addition of GTP
Study Notes
- Today's lecture topic: Structure and processing of mRNA molecules in eukaryotes and prokaryotes
- Bacterial and eukaryotic mRNA molecules differ in structure: operon, 5' UTR, 3'UTR
- Pre-mRNA processing starts cotranscriptionally
- RNA processing factors are recruited by the phosphorylated carboxy-terminal domain (CTD) of RNA polymerase II
- Eukaryotic mRNAs undergo 5'cap formation, which marks the RNA as mRNA, protects it from degradation, and promotes translation
- Splicing is the process of removing introns from the pre-mRNA
- Introns are much longer than exons, and the splicing machinery achieves specificity through base-pairing between non-coding RNAs (snRNAs) and the pre-mRNA splice sites
- The spliceosome, a large complex of snRNAs and proteins, mediates pre-mRNA splicing
- Alternative splicing generates multiple mRNA isoforms from a single gene, leading to protein diversity
- Drosophila's DSCAM gene is the most extreme example of alternative splicing, with the potential to produce over 38,000 isoforms.
Test your knowledge on RNA biology and posttranscriptional gene regulation with this quiz. Includes topics such as RNA processing in the nucleus, life and death of mRNAs in the cytoplasm, and non-coding RNA.
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