Gene Silencing Flashcards
What does RNA interference (RNAi) do
Prevents (silences) translation of native genes
Acts as a cellular defence mech against viral infections
What is Anti-sense RNA
15-20bp long oligonucleotides complementary positive sense RNA
What is anti-sense RNA used for in the lab
Used in research to identify loss-of-function phenotype by inhibiting expression with synaptic anti-sense RNA.
How can Anti-sense RNA be used as a treatment/therapy
To treat disease caused by expression of deleterious genes e.g. viral infections l, cancer, inflammatory disease
What are the two types of endogenous dsRNA
Hairpin dsRNA (microRNA miRNA 21-22bp) Linear dsRNA (small interfering siRNA 20-25bp)
Describe the characteristics of miRNA
Distinct non-protein coding miRNA genes that degrade target mRNAs or block mRNA translation
Describe the characteristics of siRNA
They’re from transposable elements in the genome that silence transposons and regulate genes
Describe Piwi-interacting RNA
piRNA 26-31nt (ss), silences transposons
True or false: miRNA regulates translation of 1/4 of all genes
False, regulates 1/3
What is Drosha
- RNAse 3-Type endonuclease that produces a 1-nucleotide 3’ overhang
- processes Primary miRNA TO GENERWTE 70-80nt Precursor miRNAs
What is Dicer
- RNAse 3-Type endonuclease that cuts hairpins and produces nature miRNA from pre-miRNAs and initiates the formation of argonaut protein family
What is RISC
RNA-Induced Silencing Complex: ribonucleoprotein complex containing members of Argonaut protein family
What are the functions of RISC
- Selection of miR guide and miR* passenger miRNA strand
- Selection of activity against miRNA complementary bound guide miRNA or siRNA
- Translation repression of mRNA weakly bound to guide miRNA
Is Drosha involves with the processing of siRNAi
No because they are already double stranded
