RNA Splicing and Spliceosome Quiz

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Questions and Answers

What is the key part of adaptive immunity in non-eukaryotes?

Cas9 protein

CRISPR DNA sequences (correct)

piRNAs and Piwis

Exons

What is now used to create knock-out or knock-in mutations?

piRNAs

Exons

Cas proteins

CRISPR/Cas9 (correct)

What greatly improves prospects for genetic surgery?

piRNAs and Piwis

Cas9 protein

Introns

CRISPR Prime Editing (correct)

What is the role of U# snRNPs in splicing?

They act as guards to ensure proper binding of pre-mRNA. Signup and view all the answers

What is the function of SR proteins in splicing?

They recruit spliceosome components to the 5′ end and 3′ splice sites. Signup and view all the answers

What is an example of alternative splicing?

Exon skipping Signup and view all the answers

What distinguishes the minor spliceosome from the major spliceosome?

Recognition of distinct 5′ and 3′ splice sites Signup and view all the answers

What is the role of the spliceosome in splicing?

Recognizes and binds to the 5’ splice site, the branch site, and the 3’ splice site, and catalyzes RNA cleavage and joining reactions Signup and view all the answers

What is the function of Group I introns in splicing?

Release a linear intron Signup and view all the answers

How do self-splicing introns differ from spliceosome-dependent splicing?

Self-splicing introns do not require the spliceosome and are usually shorter than Group II introns Signup and view all the answers

What are the two ways to ensure accuracy in splicing and reduce exon skipping?

<ol> <li>Transfer of splicing factors from RNA polymerase CTD to the 5′ splice site, poised & ready to react with the next 3′ site. 2) Ensure that only splice sites next to exons are selected by SR proteins binding to Exonic Splicing Enhancers (ESE) and recruiting components of the splicing machinery.</li> </ol> Signup and view all the answers

What is trans-splicing and how does it differ from traditional splicing?

Trans-splicing is the fusion of exons from different RNA molecules, allowing exon skipping and alternative splicing. It differs from traditional splicing in that it can join exons that are not necessarily the nextmost ones or even from completely different mRNAs. Signup and view all the answers

What is the function of the minor spliceosome and how does it differ from the major spliceosome?

The minor spliceosome recognizes distinct 5′ and 3′ splice sites but uses the same splicing process as the major spliceosome. It splices a small group of introns using a different set of snRNPs, providing more specificity in splicing. Signup and view all the answers

What is the role of SR proteins in splicing and how do they contribute to proper splicing?

SR proteins (Serine-aRginine rich) bind to Exonic Splicing Enhancers (ESE) and recruit components of the splicing machinery to ensure accurate splicing. They help direct splicing to proper sites and reduce exon skipping. Signup and view all the answers

Explain the process of mRNA splicing, including the key components and their roles in the splicing process.

mRNA splicing is the process of removing intervening introns from pre-mRNA and joining the protein-encoding exons to form mature mRNA. This process is carried out by the spliceosome, a large complex consisting of 150 proteins and 5 RNAs, including U1, U2, U4, U5, and U6 snRNAs. The spliceosome recognizes and binds to the 5’ splice site, the branch site, and the 3’ splice site, and catalyzes RNA cleavage and joining reactions through sequential transesterification events. Alternative splicing can yield different proteins from the same gene, and the type of splicing determines if the spliceosome is needed, the branch site used, and the final intron type. Signup and view all the answers

Discuss the potential evolutionary relationship between Group II self-splicing introns and the spliceosome.

It is believed that spliceosomes may have evolved from Group II self-splicing introns, as they share the same structure as spliceosome’s snRNPs. Group II introns are self-splicing introns that usually require a free G-site branch site, and they are well-conserved and usually shorter than other self-splicing introns. The similarities in structure and function between Group II introns and the spliceosome suggest a potential evolutionary relationship between the two. Signup and view all the answers

How does splicing contribute to the generation of isoforms from the same gene, and what implications does this have for eukaryotic complexity?

Splicing can yield different proteins from the same gene through alternative splicing, resulting in isoforms. This process allows for the production of multiple protein variants from a single gene, greatly increasing the proteomic diversity and functional complexity of eukaryotic organisms. As eukaryotic complexity increases, the intron content per gene also increases, indicating a potential relationship between splicing and the complexity of eukaryotic organisms. Signup and view all the answers

Explain the role of CRISPR/Cas9 in genetic engineering and the implications of mutated Cas9 nucleases.

CRISPR/Cas9 is used to create knock-out or knock-in mutations by targeting specific DNA sequences for modification. Mutated Cas9 nucleases increase the possibilities of genetic engineering by allowing for more precise and diverse genetic alterations, but also raise concerns about off-target effects and unintended mutations. Signup and view all the answers

Discuss the significance of CRISPR Prime Editing in the field of genetic surgery.

CRISPR Prime Editing greatly improves prospects for genetic surgery by enabling more precise and efficient modification of genetic material. This technology offers the potential for permanent human genetic alteration and has implications for treating genetic disorders and diseases. Signup and view all the answers

Describe the process of RNA splicing in eukaryotic genes, including the role of exons, introns, and the proteins involved in splicing.

RNA splicing in eukaryotic genes involves the removal of introns and the joining of exons to form a mature mRNA molecule. This process is facilitated by the spliceosome and various splicing proteins, which work together to accurately remove introns and ligate exons. The fidelity of splicing is maintained through the coordination of these proteins, as well as the recognition of splice sites and the correction of splicing errors. Signup and view all the answers

Study Notes

RNA Splicing and the Spliceosome: Key Mechanisms and Processes

Eukaryotic genes can lack introns, but intron content per gene increases with eukaryotic complexity.
In mRNA splicing, intervening introns are removed, leaving protein-encoding exons.
Splicing can yield different proteins from the same gene through alternative splicing, resulting in isoforms.
The splicing process involves 5’ (donor) and 3’ (acceptor) splice sites, as well as internal branch sites.
Splicing is carried out by a large complex called the spliceosome, consisting of 150 proteins and 5 RNAs, similar in size to the ribosome.
Spliceosome assembly and rearrangements involve RNA-RNA hybrids and proteins, such as U1, U2, U4, U5, and U6 snRNAs.
The spliceosome recognizes and binds to the 5’ splice site, the branch site, and the 3’ splice site, and catalyzes RNA cleavage and joining reactions.
The spliceosome undergoes sequential transesterification events, allowing for intron self-splicing and self-ligation.
Self-splicing introns, which do not require the spliceosome, are well-conserved and usually shorter than Group II introns.
The splicing type determines if the spliceosome is needed, the branch site used, and the final intron type.
Group I introns release a linear intron, while Group II introns use a free G-site branch site.
Spliceosomes may have evolved from Group II self-splicing introns, as they share the same structure as spliceosome’s snRNP.

RNA Splicing and the Spliceosome: Key Mechanisms and Processes

Eukaryotic genes can lack introns, but intron content per gene increases with eukaryotic complexity.
In mRNA splicing, intervening introns are removed, leaving protein-encoding exons.
Splicing can yield different proteins from the same gene through alternative splicing, resulting in isoforms.
The splicing process involves 5’ (donor) and 3’ (acceptor) splice sites, as well as internal branch sites.
Splicing is carried out by a large complex called the spliceosome, consisting of 150 proteins and 5 RNAs, similar in size to the ribosome.
Spliceosome assembly and rearrangements involve RNA-RNA hybrids and proteins, such as U1, U2, U4, U5, and U6 snRNAs.
The spliceosome recognizes and binds to the 5’ splice site, the branch site, and the 3’ splice site, and catalyzes RNA cleavage and joining reactions.
The spliceosome undergoes sequential transesterification events, allowing for intron self-splicing and self-ligation.
Self-splicing introns, which do not require the spliceosome, are well-conserved and usually shorter than Group II introns.
The splicing type determines if the spliceosome is needed, the branch site used, and the final intron type.
Group I introns release a linear intron, while Group II introns use a free G-site branch site.
Spliceosomes may have evolved from Group II self-splicing introns, as they share the same structure as spliceosome’s snRNP.

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Description

Test your knowledge of RNA splicing and the spliceosome with this quiz. Explore key mechanisms and processes, including intron removal, alternative splicing, spliceosome assembly, and splicing types. Dive into the world of RNA splicing and enhance your understanding of this essential biological process.