Regulatory RNAs and Gene Regulation Quiz

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Questions and Answers

What is the role of regulatory RNAs according to the text?

  • Serve as raw material for dsRNA formation
  • Block ribosome formation
  • Act as templates for protein-coding genes
  • Regulate gene transcription and translation (correct)

What is the function of RNA interference (RNAi) in eukaryotes?

  • Induce dsRNA formation
  • Promote gene transcription
  • Increase translation of genes
  • Repress/silence genes with homologous short RNAs (correct)

What is the current understanding of 'junk DNA' mentioned in the text?

  • It has no function in gene regulation
  • It is involved in ribosome formation
  • It is now known as a template for non-protein coding RNAs (correct)
  • It serves as a raw material for protein synthesis

What can be inferred about eukaryotic gene regulation based on the text?

<p>Eukaryotes have fewer protein-coding genes than originally predicted (B)</p> Signup and view all the answers

RNA interference (RNAi) uses long RNAs to bind & shut off matching regions in target genes.

<p>False (B)</p> Signup and view all the answers

MicroRNAs (miRNAs) downregulate RNAs by translational repression and mRNA decay.

<p>True (A)</p> Signup and view all the answers

MiRNAs always originate from the same part of an RNA molecule.

<p>False (B)</p> Signup and view all the answers

RNA interference (RNAi) is a well-used method of choice to enhance gene expression in model organisms.

<p>False (B)</p> Signup and view all the answers

Eukaryotes were originally predicted to have fewer protein-coding genes based on genome size.

<p>False (B)</p> Signup and view all the answers

NcRNAs are now known to have no regulatory roles in gene expression.

<p>False (B)</p> Signup and view all the answers

DGCR8, Drosha, and Pasha form the microprocessor complex for microRNA biogenesis

<p>True (A)</p> Signup and view all the answers

Dicer is the second RNA-cleaving enzyme involved in miRNA production

<p>True (A)</p> Signup and view all the answers

SiRNAs are made from longer dsRNAs and do not require Drosha

<p>True (A)</p> Signup and view all the answers

RNAi likely evolved as an ancient immune system used for gene regulation

<p>True (A)</p> Signup and view all the answers

What is the role of regulatory RNAs according to the text?

<p>Regulatory RNAs serve as regulators of gene transcription and translation.</p> Signup and view all the answers

What can be inferred about eukaryotic gene regulation based on the text?

<p>Eukaryotic gene regulation involves the use of regulatory RNAs to alter gene transcriptional activity for the purpose of studying gene function and medical applications.</p> Signup and view all the answers

How does RNA interference (RNAi) function as a major regulatory mechanism in eukaryotes?

<p>RNA interference (RNAi) involves very short RNAs that can repress or silence genes with homology to these short RNAs, thereby inhibiting gene expression.</p> Signup and view all the answers

What was formerly believed to be 'junk DNA' and what is its current understanding?

<p>Formerly believed to be 'junk DNA,' non-protein coding RNAs are now known to serve as the template for regulatory RNAs with important roles in gene regulation.</p> Signup and view all the answers

How can the knowledge of regulatory RNAs be exploited for experimental purposes, according to the text?

<p>The knowledge of regulatory RNAs can be exploited to experimentally alter gene transcriptional activity in order to study gene function and for medical purposes.</p> Signup and view all the answers

What are the components of the microprocessor complex for microRNA biogenesis?

<p>DGCR8, Drosha, and Pasha</p> Signup and view all the answers

What is the role of Dicer in miRNA production?

<p>Dicer recognizes the Drosha-cleaved pre-miRNA and cleaves off the terminal loop</p> Signup and view all the answers

What is the function of the Argonaute protein in the RISC complex?

<p>The Argonaute protein is the 'slicer' protein in the RISC complex, which pairs miRNA &amp; target mRNA for silencing</p> Signup and view all the answers

How can RNAi be exploited for gene regulation?

<p>RNAi can be exploited to artificially silence target genes</p> Signup and view all the answers

How do plants use RNAi to suppress viral genes?

<p>Plants use RNAi to suppress viral genes by spreading siRNAs made from the viral genome</p> Signup and view all the answers

What are the three main classes of small RNAs in eukaryotes?

<p>MicroRNAs (miRNAs), Small interfering RNAs (siRNAs), Repeat-associated small interfering RNAs (rasiRNAs)</p> Signup and view all the answers

What is the role of Argonaute-family proteins in RNA-induced gene silencing?

<p>They facilitate interactions with targets, denature the RNA, and allow it to bind to matching regions in mRNA or genome. They can recruit chromatin remodeling enzymes when targeted to the nucleus and modify promoters, leading to gene silencing.</p> Signup and view all the answers

How are miRNAs processed and activated?

<p>Each pre-miRNA is composed of 2 'arms' on either side of the hairpin’s loop within the primary miRNA. The primary miRNA (pri-miRNA) is a precursor made of hairpin RNA plus ssRNA sequence, cleaved by 'DROSHA' RNase to give hairpin precursor miRNA (pre-miRNA). Second RNase cleavage reaction by DICER liberates the mature miRNA sequences. miRNAs need to undergo post-transcriptional processing to activate them.</p> Signup and view all the answers

How can RNA-Dependent RNA Polymerase (RDRP) amplify the RNAi process?

<p>RISC can recruit RDRP to make even more dsRNA precursor, which amplifies the RNAi signal.</p> Signup and view all the answers

What is the characteristic structure of pre-miRNAs and how does it assist in identifying them and their target genes?

<p>Each pre-miRNA has two arms, each of which may have their own targets. The 'seed region' (bases 2-9) has high complementarity to target RNA and can help identify targets. Pre-miRNAs can yield 1-2 miRNAs that bind complementary target regions. Pre-miRNA may be found in any part of an RNA molecule, including exons, introns, and leader sequences.</p> Signup and view all the answers

What are the components of the microprocessor complex for microRNA biogenesis?

<p>DGCR8, Drosha, and Pasha</p> Signup and view all the answers

What is the role of Dicer in miRNA production?

<p>Dicer recognizes the Drosha-cleaved pre-miRNA and cleaves off the terminal loop</p> Signup and view all the answers

How do plants use RNAi to suppress viral genes?

<p>Plants use RNAi to suppress viral genes by spreading siRNAs made from the viral genome</p> Signup and view all the answers

What is the function of the Argonaute protein in the RISC complex?

<p>Argonaute protein is the 'slicer' protein in the RISC complex, which pairs miRNA &amp; target mRNA for silencing</p> Signup and view all the answers

How can RNAi be exploited to artificially silence target genes?

<p>RNAi can be exploited to artificially silence target genes</p> Signup and view all the answers

What is the role of regulatory RNAs according to the text?

<p>Regulatory RNAs serve as regulators of gene transcription and translation, and they have been exploited to experimentally alter gene transcriptional activity for studying gene function and medical purposes.</p> Signup and view all the answers

How does RNA interference (RNAi) function as a major regulatory mechanism in eukaryotes?

<p>RNA interference (RNAi) involves very short RNAs that can repress or silence genes with homology to these short RNAs. It can cause inhibition of gene translation, formation and destruction of double-stranded RNA, as well as binding of short RNAs to gene promoters to block them.</p> Signup and view all the answers

What was formerly believed to be 'junk DNA' and what is its current understanding?

<p>Formerly believed to be 'junk DNA,' non-coding RNAs (ncRNAs) are now known to have regulatory roles in gene expression.</p> Signup and view all the answers

How can the knowledge of regulatory RNAs be exploited for experimental purposes, according to the text?

<p>The knowledge of regulatory RNAs can be exploited to experimentally alter gene transcriptional activity for studying gene function and for medical purposes.</p> Signup and view all the answers

What can be inferred about eukaryotic gene regulation based on the text?

<p>Eukaryotic gene regulation involves the use of regulatory RNAs that have been found to serve as regulators of gene transcription and translation. This knowledge has been exploited to experimentally alter gene transcriptional activity for studying gene function and medical purposes.</p> Signup and view all the answers

What are the three main classes of small RNAs in eukaryotes?

<p>The three main classes of small RNAs in eukaryotes are MicroRNAs (miRNAs), Small interfering RNAs (siRNAs), and Repeat-associated small interfering RNAs (rasiRNAs)</p> Signup and view all the answers

How are miRNAs processed and activated?

<p>MiRNAs are processed and activated through a 2-step nucelolytic processing. Drosha cuts the pri-mRNA to liberate pre-miRNA with help of a specificity subunit protein (Pasha a.k.a. DGCR8)</p> Signup and view all the answers

What is the function of the Argonaute protein in the RISC complex?

<p>The Argonaute protein in the RISC complex is responsible for matching interfering RNA with target in mRNA or genome. It can denature the RNA and allows it to bind to matching regions to interfere with gene expression.</p> Signup and view all the answers

How can RNA-Dependent RNA Polymerase (RDRP) amplify the RNAi process?

<p>RNA-Dependent RNA Polymerase (RDRP) can be recruited by RISC and make even more dsRNA precursor which amplifies the RNAi process.</p> Signup and view all the answers

What is the characteristic structure of pre-miRNAs and how does it assist in identifying them and their target genes?

<p>Pre-miRNAs have two arms, each of which may have their own targets. They have a characteristic structure with a 'seed region' (bases 2-9) that has high complementarity to target RNA and can help identify targets.</p> Signup and view all the answers

What are the components of the microprocessor complex for microRNA biogenesis?

<p>DGCR8, Drosha, and Pasha</p> Signup and view all the answers

What is the role of Dicer in miRNA production?

<p>Dicer recognizes the Drosha-cleaved pre-miRNA and cleaves off the terminal loop</p> Signup and view all the answers

What is the function of the Argonaute protein in the RISC complex?

<p>Argonaute protein is the 'slicer' protein in the RISC complex, which pairs miRNA &amp; target mRNA for silencing</p> Signup and view all the answers

How do plants use RNAi to suppress viral genes?

<p>Plants use RNAi to suppress viral genes by spreading siRNAs made from the viral genome</p> Signup and view all the answers

What is the function of RNA interference (RNAi) in eukaryotes?

<p>RNA interference (RNAi) likely evolved as an ancient immune system used for gene regulation and can be exploited to artificially silence target genes</p> Signup and view all the answers

What is the current understanding of 'junk DNA' mentioned in the text?

<p>RNAs can serve as regulators of gene transcription and translation, and RNAi uses very short RNAs to bind and shut off matching regions in target genes</p> Signup and view all the answers

What is the characteristic structure of pre-miRNAs and how does it assist in identifying them and their target genes?

<p>Drosha cleaves pri-mRNA to yield pre-mRNA containing upper stem + loop, and Dicer recognizes and cleaves off the terminal loop</p> Signup and view all the answers

What is the role of regulatory RNAs according to the text?

<p>RNAs can serve as regulators of gene transcription and translation, and RNAi uses very short RNAs to bind and shut off matching regions in target genes</p> Signup and view all the answers

How can the knowledge of regulatory RNAs be exploited for experimental purposes, according to the text?

<p>RNAi can be exploited to artificially silence target genes and suppress viral genes in plants</p> Signup and view all the answers

What can be inferred about eukaryotic gene regulation based on the text?

<p>Eukaryotic gene regulation involves the use of RNAi and regulatory RNAs to control gene expression</p> Signup and view all the answers

What term is used to describe what was formerly believed to be 'junk DNA' and what is its current understanding?

<p>formerly believed to be 'junk DNA' is now known as template for non-protein coding RNAs</p> Signup and view all the answers

What is the major regulatory mechanism in eukaryotes that involves very short RNAs repressing/silencing genes with homology to these short RNAs?

<p>RNA interference (RNAi)</p> Signup and view all the answers

What is the function of RNA interference (RNAi) as a major regulatory mechanism in eukaryotes?

<p>RNA interference (RNAi) is a well-used method of choice to suppress gene expression in model organisms to study gene function</p> Signup and view all the answers

How can the knowledge of regulatory RNAs be exploited for experimental purposes, according to the text?

<p>Can now exploit regulatory RNA knowledge to experimentally alter gene transcriptional activity to study gene function, medical purposes</p> Signup and view all the answers

What can be inferred about eukaryotic gene regulation based on the text?

<p>eukaryotes were originally predicted to have far more protein-coding genes based on genome size but were later found by genome analysis to have far fewer proteins</p> Signup and view all the answers

What is the role of regulatory RNAs according to the text?

<p>RNAs can serve as regulators of gene transcription and translation</p> Signup and view all the answers

What is the function of the Argonaute protein in the RISC complex?

<p>The Argonaute protein in the RISC complex helps in the RNA interference process by binding to the short RNAs and leading to gene silencing</p> Signup and view all the answers

How does RNA interference (RNAi) function as a major regulatory mechanism in eukaryotes?

<p>RNA interference (RNAi) can cause inhibition of translation of gene, formation and destruction of dsRNA, and short RNA binding to gene’s promoter to block it</p> Signup and view all the answers

What is the characteristic structure of pre-miRNAs and how does it assist in identifying them and their target genes?

<p>Pre-miRNAs have a characteristic hairpin structure and this structure helps in identifying them and their target genes</p> Signup and view all the answers

What is the role of Dicer in miRNA production?

<p>Dicer is the second RNA-cleaving enzyme involved in miRNA production</p> Signup and view all the answers

Explain the role of RNA interference (RNAi) in gene regulation in eukaryotes and provide examples of its importance in development and defense mechanisms.

<p>RNA interference (RNAi) is a regulatory mechanism in eukaryotes that uses very short RNAs to bind and shut off matching regions in target genes. It plays an important role in development and antiviral defense. Examples include the importance of RNAi in C. elegans and plant (Arabidopsis) research.</p> Signup and view all the answers

Describe the three main classes of small RNAs in eukaryotes and their respective functions.

<p>The three main classes of small RNAs in eukaryotes are MicroRNAs (miRNAs), Small interfering RNAs (siRNAs), and Repeat-associated small interfering RNAs (rasiRNAs). MiRNAs usually downregulate RNAs by translational repression and mRNA decay, siRNAs target RNAs for degradation as a cellular defense mechanism, and rasiRNAs downregulate transcription from repetitive regions.</p> Signup and view all the answers

What are the components of the RNA-Induced Silencing Complex (RISC) and how do they function in gene silencing?

<p>The components of the RNA-Induced Silencing Complex (RISC) include Argonaute-family proteins and small RNAs. RISC denatures the RNA and allows it to bind to matching regions in target genes, causing mRNA destruction or inhibiting translation. The Argonaute-family proteins facilitate interactions with targets.</p> Signup and view all the answers

Explain the process of miRNA biogenesis, including the role of DROSHA and DICER.

<p>The process of miRNA biogenesis involves the cleavage of primary miRNA (pri-miRNA) by 'DROSHA' RNase to give hairpin precursor miRNA (pre-miRNA), which are then exported to the cytosol. Subsequent cleavage by DICER liberates the mature miRNA sequences.</p> Signup and view all the answers

How can RNA-Dependent RNA Polymerase (RDRP) amplify the RNAi process, and what role does it play in enhancing gene silencing?

<p>RNA-Dependent RNA Polymerase (RDRP) can be recruited by RISC and make even more dsRNA precursor, which amplifies the RNAi process. This enhances gene silencing by producing additional small RNAs to target and shut off matching regions in genes.</p> Signup and view all the answers

What is the characteristic structure of pre-miRNAs and how does it assist in identifying them and their target genes?

<p>Pre-miRNAs have two 'arms,' each of which may have their own targets. The 'seed region' (bases 2-9) has high complementarity to target RNA and helps identify targets. Pre-miRNAs may be found in any part of an RNA molecule, including exons, introns, and leader sequences.</p> Signup and view all the answers

Explain how miRNAs undergo post-transcriptional processing to activate them and their role in gene regulation.

<p>miRNAs need to undergo post-transcriptional processing, which involves cleavage by DICER and miRNA-specific RNase called Drosha/DGCR8. Once activated, miRNAs can bind complementary target regions and regulate gene expression.</p> Signup and view all the answers

Describe the role of RNA-Induced Silencing Complex (RISC) in gene silencing and its interaction with target genes.

<p>The RNA-Induced Silencing Complex (RISC) denatures the RNA and allows it to bind to matching regions in target genes. Perfect target matches cause mRNA destruction, while imperfect target matches inhibit translation. RISC proteins are needed to match interfering RNA with targets in mRNA or the genome.</p> Signup and view all the answers

Explain the role of Argonaute-family proteins in the RISC complex and their function in RNA-induced gene silencing.

<p>Argonaute-family proteins in the RISC complex facilitate interactions with target genes and can recruit chromatin remodelling enzymes when targeted to the nucleus. They also modify promoters, leading to gene silencing. Additionally, they can function as &quot;Slicer&quot; proteins, causing mRNA cleavage.</p> Signup and view all the answers

How can small RNAs derived from different sources be used in various ways to silence genes, and what are the different pathways through which gene silencing can occur?

<p>Small RNAs derived from different sources can be used to silence genes through translational repression, mRNA decay, and mRNA destruction. The different pathways include gene silencing through MicroRNAs (miRNAs), Small interfering RNAs (siRNAs), and Repeat-associated small interfering RNAs (rasiRNAs).</p> Signup and view all the answers

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Study Notes

RNA Interference and microRNA Biogenesis

  • DGCR8, Drosha, and Pasha form the microprocessor complex for microRNA biogenesis
  • Drosha cleaves pri-mRNA to yield pre-mRNA containing upper stem + loop
  • Dicer is the second RNA-cleaving enzyme involved in miRNA production
  • Dicer recognizes the Drosha-cleaved pre-miRNA and cleaves off the terminal loop
  • Argonaute protein is the 'slicer' protein in the RISC complex, which pairs miRNA & target mRNA for silencing
  • siRNAs are made from longer dsRNAs and do not require Drosha
  • RNAi likely evolved as an ancient immune system used for gene regulation
  • The RNAi machinery may have been recruited for use with miRNAs to regulate gene expression
  • RNAi can be exploited to artificially silence target genes
  • Plants use RNAi to suppress viral genes by spreading siRNAs made from the viral genome
  • Viruses have retaliated by producing anti-RNAi proteins to counteract the RNAi defense mechanism
  • RNAs can serve as regulators of gene transcription and translation, and RNAi uses very short RNAs to bind and shut off matching regions in target genes

RNA Interference and microRNA Biogenesis

  • DGCR8, Drosha, and Pasha form the microprocessor complex for microRNA biogenesis
  • Drosha cleaves pri-mRNA to yield pre-mRNA containing upper stem + loop
  • Dicer is the second RNA-cleaving enzyme involved in miRNA production
  • Dicer recognizes the Drosha-cleaved pre-miRNA and cleaves off the terminal loop
  • Argonaute protein is the 'slicer' protein in the RISC complex, which pairs miRNA & target mRNA for silencing
  • siRNAs are made from longer dsRNAs and do not require Drosha
  • RNAi likely evolved as an ancient immune system used for gene regulation
  • The RNAi machinery may have been recruited for use with miRNAs to regulate gene expression
  • RNAi can be exploited to artificially silence target genes
  • Plants use RNAi to suppress viral genes by spreading siRNAs made from the viral genome
  • Viruses have retaliated by producing anti-RNAi proteins to counteract the RNAi defense mechanism
  • RNAs can serve as regulators of gene transcription and translation, and RNAi uses very short RNAs to bind and shut off matching regions in target genes

RNA Interference and microRNA Biogenesis

  • DGCR8, Drosha, and Pasha form the microprocessor complex for microRNA biogenesis
  • Drosha cleaves pri-mRNA to yield pre-mRNA containing upper stem + loop
  • Dicer is the second RNA-cleaving enzyme involved in miRNA production
  • Dicer recognizes the Drosha-cleaved pre-miRNA and cleaves off the terminal loop
  • Argonaute protein is the 'slicer' protein in the RISC complex, which pairs miRNA & target mRNA for silencing
  • siRNAs are made from longer dsRNAs and do not require Drosha
  • RNAi likely evolved as an ancient immune system used for gene regulation
  • The RNAi machinery may have been recruited for use with miRNAs to regulate gene expression
  • RNAi can be exploited to artificially silence target genes
  • Plants use RNAi to suppress viral genes by spreading siRNAs made from the viral genome
  • Viruses have retaliated by producing anti-RNAi proteins to counteract the RNAi defense mechanism
  • RNAs can serve as regulators of gene transcription and translation, and RNAi uses very short RNAs to bind and shut off matching regions in target genes

RNA Interference and microRNA Biogenesis

  • DGCR8, Drosha, and Pasha form the microprocessor complex for microRNA biogenesis
  • Drosha cleaves pri-mRNA to yield pre-mRNA containing upper stem + loop
  • Dicer is the second RNA-cleaving enzyme involved in miRNA production
  • Dicer recognizes the Drosha-cleaved pre-miRNA and cleaves off the terminal loop
  • Argonaute protein is the 'slicer' protein in the RISC complex, which pairs miRNA & target mRNA for silencing
  • siRNAs are made from longer dsRNAs and do not require Drosha
  • RNAi likely evolved as an ancient immune system used for gene regulation
  • The RNAi machinery may have been recruited for use with miRNAs to regulate gene expression
  • RNAi can be exploited to artificially silence target genes
  • Plants use RNAi to suppress viral genes by spreading siRNAs made from the viral genome
  • Viruses have retaliated by producing anti-RNAi proteins to counteract the RNAi defense mechanism
  • RNAs can serve as regulators of gene transcription and translation, and RNAi uses very short RNAs to bind and shut off matching regions in target genes

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