RNA Interference: Discovery and Mechanisms

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Questions and Answers

What are the two primary types of RNA involved in the RNA interference (RNAi) pathway?

snRNA and snoRNA

mRNA and tRNA

rRNA and lncRNA

miRNA and siRNA (correct)

Which RNA type is genomically encoded and generally consists of a stem-loop structure?

miRNA (correct)

shRNA

lncRNA

siRNA

What is the primary function of small interfering RNA (siRNA) in the RNA interference mechanism?

To regulate protein translation

To silence mRNA (correct)

To assist in DNA replication

To enhance gene expression

Where does RNA interference primarily occur?

In eukaryotic organisms Signup and view all the answers

What is the size range of miRNA molecules typically found in the RNA interference pathway?

20-25 nucleotides Signup and view all the answers

Which of the following RNA types is derived from exogenous double-stranded RNA?

siRNA Signup and view all the answers

Which type of RNA is specifically recognized in the RNA-induced silencing complex?

siRNA Signup and view all the answers

What is the role of antisense RNA in plants regarding RNA interference?

To silence specific mRNA Signup and view all the answers

What is the role of RNA interference (RNAi) in plants?

It serves as a defense mechanism against pathogens. Signup and view all the answers

Which organism is mentioned as notably absent from the RNAi mechanism?

Saccharomyces cerevisiae Signup and view all the answers

What enables bacterial small noncoding RNAs to silence genes?

Translational repression. Signup and view all the answers

What is a function of RNAi beyond gene regulation?

Degrading pathogen mRNAs. Signup and view all the answers

What is required for achieving RNA interference with synthetic RNA?

Synthesis of dsRNA or pre-miRNA specific to target mRNA. Signup and view all the answers

What does the term 'knock-down' refer to in the context of RNAi?

Reduction of protein product levels. Signup and view all the answers

In which of the following organisms can RNAi be used as a research tool to study protein functions?

In many model organisms. Signup and view all the answers

What is the role of Dicer and Argonaute in yeast RNAi?

They are involved in RNAi mechanisms. Signup and view all the answers

What is a notable advantage of using RNA interference (RNAi) in biotechnology?

It does not change the gene being targeted. Signup and view all the answers

Which of the following statements about RNAi-based therapeutics is true?

RNAi allows for specific depletion of target mRNA/protein. Signup and view all the answers

What is a challenge associated with delivering RNAi therapy?

RNA often gets treated as a foreign substance. Signup and view all the answers

As of July 2023, how many ongoing clinical trials involving RNAi were reported?

48 Signup and view all the answers

Which of the following is NOT considered a pro of RNAi in biotechnology?

Short-term effect. Signup and view all the answers

Which of the following RNAi-based medications have been approved?

Inclisiran Signup and view all the answers

What does the RNA-induced silencing complex primarily do?

Silences gene expression. Signup and view all the answers

What is a potential disadvantage of RNA interference technology?

It can incur short-term effects. Signup and view all the answers

Study Notes

RNA Interference Overview

RNA interference (RNAi) is a biological process regulating gene expression by silencing specific mRNAs.
Both microRNA (miRNA) and small interfering RNA (siRNA) play roles in gene regulation through RNAi.

Discovery and Mechanism

Many genes yield RNA products, including mRNA, tRNA, rRNA, snRNA, snoRNA, lncRNA, miRNA, piRNA, siRNA, and short hairpin RNA (shRNA).
miRNA is genomically encoded and typically has a single-stranded stem-loop structure, approximately 20-25 base pairs long (~22nt).
siRNA originates from exogenous double-stranded RNA and operates through an RNA-induced silencing complex (RISC).

Variation Across Organisms

RNAi functions primarily in eukaryotes but is not universally present in all eukaryotic organisms; lacking notably in budding yeast (Saccharomyces cerevisiae).
RNAi is more prevalent in plants, where it is heritable, unlike in mammals.
RNAi also serves as a defense mechanism against pathogens, allowing degradation of foreign mRNA.

Synthetic RNA and Gene Silencing

Synthetic RNA, such as dsRNA or pre-miRNA, can be introduced to target mRNA, enabling gene-specific degradation and protein knock-down.
RNAi serves as a lab tool to explore protein functions across various model organisms.

Biotechnology Applications

RNA interference in plants is utilized to manage pests and diseases, enhance crop quality, improve abiotic stress tolerance, and induce male sterility.
Advantages include no permanent gene alteration, while disadvantages include potential off-target effects, short-term efficacy, and delivery challenges.

Therapeutic Potential

RNAi is a vital mechanism for silencing gene expression, offering pathways for new drug development.
The RNAi machinery (Dicer and Argonaute proteins) is found in all human cells, allowing precise targeting of mRNA/protein without modifying genomic DNA.
Shorter development times compared to traditional antibodies and small chemical drugs are advantageous for RNAi therapies.

Clinical Trials and Challenges

From 1998 to 2022, there were 90 reported clinical trials on RNAi therapies, with 48 ongoing as of July 2023.
Six RNAi-based drugs have received approval in the US and Europe: Patisiran, Givosiran, Lumasiran, Inclisiran, Vutrisiran, and Rivfloza.
Challenges in RNAi therapy include potential immune responses, treating RNA as foreign material without proper modification, and potential off-target effects.

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Description

This quiz explores the discovery of RNA interference and its significance in gene expression. It covers the roles of various RNA molecules, including mRNA, tRNA, and rRNA, in the processes of transcription and translation. Test your understanding of these essential biological concepts!