Fan Flashcards
RNA interference (RNAi) is a phenomenon in which the introduction of _______ into a cell causes degradation of the complementary mRNA.
Double-stranded RNA (dsRNA)
Long dsRNAs are cleaved into short 21-25 nucleotide small interfering RNAs (siRNAs) by a ribonuclease known as _______.
Dicer-2
The siRNAs assemble with protein components into an _______, unwinding in the process.
RNA-induced silencing complex (RISC)
Activated RISC then binds to complementary transcript by _______ interactions between the siRNA strand and the mRNA.
base pairing
A serious problem for developing RNAi techniques for human cells is that the cell response to dsRNA triggers a _______ involving the release of interferon.
cellular immune response
In 2001 it was discovered that RNAi could be achieved in mammalian cells without activating the interferon response by using shorter pieces of RNA known as _______.
Small interfering RNAs (siRNAs)
An effective siRNA should have _______ at the 5’-end of the antisense strand.
A or U
An effective siRNA should have _______ at the 5’-end of the sense strand.
G or C
An effective siRNA should have more than 4 _______ nucleotides in the seed sequence (2nd-9th nt of antisense from 5’).
A or U
An effective siRNA should have _______ or _______ at the cleavage site (9-10).
A or U
An effective siRNA should have unilateral 2-nt _______.
3’-overhangs
In the past, people thought non-coding RNAs were _______.
junk (orally 10/10)
_______ (short hairpin RNA) can be used for long-term expressing double-stranded siRNA.
shRNA
The GFP-transgenic C. elegans experiment showed _________ of genes.
specific silencing
dsRNA is more _______ than single-strand RNA at silencing genes.
effective
Long dsRNA are chopped by __________, a ribonuclease.
Dicer-2
The spacer in shRNA is _______.
TCAAGAG
When dsRNA activates PKR and/OAS, it can cause ___________.
translational inhibition
siRNA may be delivered to cells for research into _______.
Determining gene/protein function
siRNA may be delivered to cells for research into _______.
partial knockdowns
siRNA may be delivered to cells for clinical research into diseases such as _______.
Cancer; hypercholesterolemia; infections; developmental defects; neurodegenerative diseases (Parkinson and Alzheimer diseases)
Besides RNAi, other examples of regulatory ncRNAs include _______.
eRNA, lncRNA
True or False: to do siRNA-mediated gene silencing, the siRNA is single-stranded.
False
For long-term expression where a gene is silenced, ________ are used.
shRNAs
The loop portion of a shRNA hairpin loop is _______ in nucleotide sequence.
TCAAGAG
The shRNA is exported from the nucleus to the cytoplasm by _______.
exportin 5 (Exp5)
To target a specific type of cell with siRNA, there needs to be ___________.
conjugation
A microRNA (miRNA) is a small non-coding RNA molecule containing about _______ nucleotides.
21-25
The first microRNA, _______, was discovered in 1993.
lin-4
More than 97% of human genome is ______.
non-coding
Small non-coding RNAs are also known as _______.
microRNAs
The second microRNA, _______, was discovered in 2000.
Let-7
Lin-4 was discovered in the organism _________.
C. elegans
miRNA genes can be located _______.
In introns of protein-coding genes, exons of protein-coding genes, or in intergenic regions
The _______ strand of a miRNA is incorporated into the miRISC complex and guides it to the target mRNA.
guide
The _______ strand of a miRNA is degraded.
passenger
The expression levels of a miRNA in cells or tissues can be determined by _______.
Deep sequencing, miRNA seq., next generation RNA seq
A miRNA recognizes its target mRNA 3’-UTR via the _______ rule.
Seed-Match
miRNA target validation can be done using a _______ assay.
reporter
miRNA levels can be reduced using _______.
AntagomiR
Long ncRNA is defined as transcripts that are longer than _______ nucleotides.
200
There are ___ classes of lncRNAs.
5
The five classes of lncRNAs are: sense, _______, bidirectional, intronic, and intergenic.
antisense
In the cytosol, some lncRNAs can act at the post-transcriptional level as _______ for miRNAs, therefore inhibiting the actions of miRNAs on mRNAs.
sponges
lncRNAs are without evidence of _________-coding capacity.
protein
True or False: circRNA is single-stranded.
True
_______ are highly abundant in cells and found in all kingdoms of life.
circRNAs
A circRNA is generated by covalently linking the _______ and _______ ends of RNA together to form a single-stranded continuous loop structure.
3’ and 5’
In the cytoplasm, circRNAs can act as a _______ for miRNAs, thereby preventing the miRNAs from binding to their target mRNAs.
sponge
The vast majority of circRNAs, particularly ecircRNAs, dominantly accumulate in _______, and EIciRNAs and ciRNAs are dominantly localized in the nucleus.
cytoplasm
