Week 5 Flashcards
what does siRNA means?
Small interfering DNA
How does siRNA match to target?
Perfect match
Is siRNA conserved across organisms? Why?
No. They are prone to mutations.
Which RNA is highly conserved across organisms?
miRNA
siRNA is mostly made from what?
retrotransposon elements
Endogenous method of siRNA production?
Transposon and repeat sequences
Exogenous method of siRNA production?
Viral or engineering transgene
What both siRNA and miRNA target?
Themselves, in order to silence.
How is siRNA made? (2 steps)
Post-transcriptional small hairpin loops or promoters on each strand, RNA polymerase and protein leads to loss of 1 strand.
What cleaves RNA?
AGO.
What miRNA does?
Codes for protein deactivation
How is miRNA formed?
-Hairpin loop structure when one part of the transcript matches with itself (inverted repeats), open end and hairpin cleaved, AGO cleaves it.
How does miRNA matches to target?
Can be perfect or imperfectly
Which sRNA matches perfectly to target always?
siRNA.
Endogenous source of miRNA?
Non protein coding genes
Exogenous source of miRNA?
Hairpin loop RNA.
What do plants miRNAs target?
Single target or only closely related sequences.
What do animals miRNAs target?
Imperfect base-pairing and multiple target sites.
What are some miRNAs associated with?
Determining cell fate/target regulatory genes that control developmental decisions
Characteristic of long non-coding RNAs (lncRNAs)?
Devoid of evident ORFs, player in cell differentiation and development.
Why target RNA? (2 points)
1 RNA –> multiple proteins.
Some proteins inaccessible to drugs.
Effects of chemical modification of RNA
more stability, resistance and binding
Morpholinos (an antisense oligonucleotide)
A synthetic oligonucleotide that replaces a base and acts by steric blocking mechanism (blocks translation).
Pros of antisense oligonucleotides for RNA manipulation
- Does not induce immune response
- Stable in cells
