RNA Interference and microRNA Biogenesis Quiz

non-coding RNAs (ncRNAs)

RNA interference (RNAi)

1. inhibition of translation of gene (blocks ribosome), 2) dsRNA formation and then destruction of dsRNA, 3) short RNA binding to gene’s promoter and block it

<p>To alter gene transcriptional activity and study gene function, for medical purposes</p> Signup and view all the answers

<p>Early work proposed a role for regulatory RNAs but evidence was lacking until the early 1990s</p> Signup and view all the answers

<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

<p>Eukaryotes have very short RNAs that can repress / silence genes that have homology to these short RNAs. This mechanism is called RNA interference (RNAi)</p> Signup and view all the answers

<p>These very short RNAs are made from longer dsRNAs by specific enzymes</p> Signup and view all the answers

<p>RNAs can serve as regulators of gene transcription and translation. These RNAs are known as regulatory RNAs.</p> Signup and view all the answers

<p>Non-coding RNAs (ncRNAs) are now known to have regulatory roles and can be exploited for experimental alteration of gene transcriptional activity for study and medical purposes</p> Signup and view all the answers

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

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

<p>Dicer is the second RNA-cleaving enzyme involved in miRNA production and recognizes the Drosha-cleaved pre-miRNA to cleave off the terminal loop</p> Signup and view all the answers

<p>Argonaute protein</p> Signup and view all the answers

<p>siRNAs are made from longer dsRNAs and do not require Drosha, unlike miRNAs</p> Signup and view all the answers

<p>RNAi likely evolved as an ancient immune system used for gene regulation and may have been recruited for use with miRNAs to regulate gene expression</p> Signup and view all the answers

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

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

<p>Viruses have retaliated by producing anti-RNAi proteins to counteract the RNAi defense mechanism</p> Signup and view all the answers

<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

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

<p>They usually downregulate RNAs by translational repression and mRNA decay.</p> Signup and view all the answers

<p>They target RNAs for degradation, serving as a cellular defense mechanism.</p> Signup and view all the answers

<p>They are derived from repetitive regions of the genome and downregulate transcription from repetitive regions.</p> Signup and view all the answers

<p>They facilitate interactions with targets and are involved in matching interfering RNA with target in mRNA or genome.</p> Signup and view all the answers

<p>RISC can denature the RNA and allow it to bind to matching regions, causing mRNA destruction or inhibiting translation.</p> Signup and view all the answers

<p>Each pre-miRNA is composed of 2 “arms” on either side of the hairpin’s loop within the primary miRNA.</p> Signup and view all the answers

<p>DICER liberates the mature miRNA sequences through a second RNase cleavage reaction.</p> Signup and view all the answers

<p>The “seed region” (bases 2-9) has high complementarity to target RNA and can help identify targets.</p> Signup and view all the answers

<p>They recognize pre-miRNA structures and help in the nucelolytic processing of miRNAs.</p> Signup and view all the answers