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Questions and Answers
What is the primary function of piRNAs in mammals?
What is the primary function of piRNAs in mammals?
PiRNAs are involved in the biogenesis of Dicer-dependent RNAs.
PiRNAs are involved in the biogenesis of Dicer-dependent RNAs.
False
What length do piRNAs typically range between?
What length do piRNAs typically range between?
25 to 33 nucleotides
Antisense oligonucleotides are _____ stranded oligonucleotides that are complementary to specific mRNA.
Antisense oligonucleotides are _____ stranded oligonucleotides that are complementary to specific mRNA.
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Which modification increases the stability of RNA oligonucleotides?
Which modification increases the stability of RNA oligonucleotides?
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Match the following elements with their corresponding colors:
Match the following elements with their corresponding colors:
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What are the two types of action that antisense oligonucleotides can perform?
What are the two types of action that antisense oligonucleotides can perform?
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PIWI proteins play a role in maintaining fertility by being involved in gametogenesis.
PIWI proteins play a role in maintaining fertility by being involved in gametogenesis.
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What is the primary function of RNA interference (RNAi)?
What is the primary function of RNA interference (RNAi)?
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RNA interference is only found in animals.
RNA interference is only found in animals.
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What enzyme is responsible for cutting long noncoding RNA into small fragments for RNA interference?
What enzyme is responsible for cutting long noncoding RNA into small fragments for RNA interference?
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RNA interference protects the genome against invasion by mobile genetic elements such as __________.
RNA interference protects the genome against invasion by mobile genetic elements such as __________.
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Match the following terms related to RNA interference with their descriptions:
Match the following terms related to RNA interference with their descriptions:
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Which organism is NOT commonly used in RNAi research?
Which organism is NOT commonly used in RNAi research?
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RNAi can only be utilized in laboratory settings and not in in vivo studies.
RNAi can only be utilized in laboratory settings and not in in vivo studies.
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What is the primary role of Antisense RNA?
What is the primary role of Antisense RNA?
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What is the size of the small RNA fragments produced by Dicer for RNA interference?
What is the size of the small RNA fragments produced by Dicer for RNA interference?
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The 5' untranslated region (5' UTR) of a gene is translated into protein.
The 5' untranslated region (5' UTR) of a gene is translated into protein.
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What are the three main regions of a typical gene?
What are the three main regions of a typical gene?
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Antisense oligonucleotides are used in biotechnology to __________ protein synthesis.
Antisense oligonucleotides are used in biotechnology to __________ protein synthesis.
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Match the following terms related to gene regulation with their descriptions:
Match the following terms related to gene regulation with their descriptions:
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Which protein is known for its role in processing RNA molecules?
Which protein is known for its role in processing RNA molecules?
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Gene silencing refers to increasing the expression of a gene.
Gene silencing refers to increasing the expression of a gene.
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What is the primary function of Argonaute proteins?
What is the primary function of Argonaute proteins?
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What is a key method by which antisense oligonucleotides (ASOs) can regulate RNA transcripts?
What is a key method by which antisense oligonucleotides (ASOs) can regulate RNA transcripts?
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All approved ASO drugs target the same disease.
All approved ASO drugs target the same disease.
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What is the purpose of attaching oligonucleotides to basic peptides?
What is the purpose of attaching oligonucleotides to basic peptides?
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The T7, T3, or SP6 RNA phage polymerase synthesizes a complementary RNA strand using _______ in place of thymine.
The T7, T3, or SP6 RNA phage polymerase synthesizes a complementary RNA strand using _______ in place of thymine.
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Match the following ASO drugs with their specific targets:
Match the following ASO drugs with their specific targets:
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What is the result of post-transcriptional gene silencing (PTGS) in plants?
What is the result of post-transcriptional gene silencing (PTGS) in plants?
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PTGS in plants is a mechanism that enhances susceptibility to viral infections.
PTGS in plants is a mechanism that enhances susceptibility to viral infections.
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Name one gene required for PTGS in plants.
Name one gene required for PTGS in plants.
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In RNA interference, small interfering RNA (siRNA) is formed from interaction with the enzyme __________.
In RNA interference, small interfering RNA (siRNA) is formed from interaction with the enzyme __________.
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Match the following RNA molecules with their functions:
Match the following RNA molecules with their functions:
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What role does Argonaute proteins play in relation to microRNAs?
What role does Argonaute proteins play in relation to microRNAs?
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MicroRNAs are produced in large numbers in humans and can be linked to various diseases.
MicroRNAs are produced in large numbers in humans and can be linked to various diseases.
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What is a common application of RNA interference in biotechnology?
What is a common application of RNA interference in biotechnology?
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Study Notes
Antisense RNA and RNA Interference (RNAi)
- Antisense RNA is a single-stranded RNA complementary to mRNA, forming a non-functional double-stranded RNA (dsRNA) strand that blocks protein synthesis.
- RNA interference (RNAi) is a biological process where microRNA (miRNA) and small interfering RNA (siRNA) inhibit gene expression by binding to mRNA and causing degradation.
- RNAi is used in biotechnology for gene knockdown in cell culture and model organisms.
Mechanisms of RNAi
- RNAi protects the genome against mobile genetic elements by targeting and degrading double-stranded RNA (dsRNA), acting as a defense against RNA viruses.
- The process of RNAi is present in various organisms, including plants, fungi, and animals, collectively referred to as gene impedance (GENEi).
Role of Dicer and Argonaute Proteins
- The enzyme Dicer cuts long noncoding RNA (lncRNA) into small fragments (~21 nucleotides) to generate siRNAs.
- Small interfering RNAs are then transferred to the RNA-induced silencing complex (RISC), where they bind to Argonaute proteins, mediating RNA degradation.
PIWI Proteins and piRNAs
- PIWI-interacting RNAs (piRNAs) are 25–33 nucleotides long and protect germ cells from transposons, being independent of Dicer for their biogenesis.
- PIWI proteins guide piRNAs to target complementary RNAs from transposable elements, leading to RNA cleavage and silencing.
Antisense Oligonucleotides (ASO)
- ASOs are single-stranded oligonucleotides, 21-24 nucleotides long, that bind specifically to mRNA, influencing RNA transcripts’ fates.
- Two types of ASO mechanisms:
- Occupancy-mediated degradation, which cleaves RNA using endogenous enzymes (e.g., RNase H).
- Occupancy-only, which regulates RNA without cleavage by altering splicing.
Applications of ASOs and RNAi in Biotechnology
- ASO therapies include drugs like Fomivirsen (for CMV retinitis), Nusinersen (for muscular dystrophy), and Volanesorsen (targeting dystrophin).
- ASOs can be synthesized in vitro by cloning into vectors, allowing for specific targeting of mRNA when transcribed in the presence of ribonucleoside triphosphates.
Post-Transcriptional Gene Silencing (PTGS)
- PTGS involves introducing transgenes or dsRNA into hosts, resulting in the selective degradation of homologous RNA populations, reducing mRNA without affecting transcription.
- In plants, PTGS serves as a defense mechanism against viral infection, reliant on specific genes like SGS3 and MET1 to function effectively.
MicroRNA and Gene Regulation
- miRNAs guide Argonaute proteins to repress mismatched mRNA, allowing one miRNA to regulate multiple genes—over 500 distinct miRNAs exist in humans.
- Aberrant miRNA production is associated with diseases, prompting the development of miRNA-inhibiting drugs for conditions such as cancer and Huntington's disease.
Delivery and Stability of Antisense Oligonucleotides
- ASOs are delivered into cells primarily via endocytosis or attachment to peptides to prevent degradation and facilitate nuclear delivery.
- Modifications enhance the stability of RNA oligonucleotides, including the use of phosphorothioate oligonucleotides and alterations to the ribose sugar to increase resistance to nucleases.
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Description
This quiz covers the concepts of antisense RNA and RNA interference (RNAi), including their mechanisms and biological significance. You will explore how RNAi inhibits gene expression and the roles of Dicer and Argonaute proteins in this process. Perfect for students interested in molecular biology and biotechnology.
