RNAi (siRNA, shRNA)

RNAi
- RNA interference. A process of mRNA cleavage and degradation that is induced by double-stranded RNA in a sequence
specific manner.
- A phenomenon in which the introduction of double-stranded RNA (dsRNA) into a diverse range of organisms and cell types
causes degradation of the complementary mRNA.

 

siRNA
- short interfering RNA. siRNAs are 19~27 bp dsRNA with dinucleotide 3’ overhangs that are processed from longer dsRNA by
Dicer in the RNAi pathway. Introduction of synthetic siRNAs can induce RNA interference in mammalian cells.

 

shRNA
- short hairpin RNA. shRNAs are used in plasmid based approaches for supplying siRNAs to cells to produce transient or
stable gene silencing.
- shRNAs are used in plasmid- or vector-based approaches for supplying isRNAs to cells to produce stable gene silencing. A
strong promoter is used to drive transcription of a target sequence designed to form hairpins and loops of variable length,
which are then processed to siRNAs by the cellular RNAi machinery.

 

miRNA
- microRNA. A large class of evolutionary conserved, noncoding, RNA originating from longer transcripts characterized by
imperfect hairpin structures. miRNAs ar 19-23 nt RNAs processed from pre-miRNA precursors by Dicer, the same enyzyme
that processes siRNAs.

 

 

 

siRNA  : cell line에서의 transfection이 잘되고, transient assay data만 필요 시

shRNA : transfection 효율이 너무 낮거나, viral delivery system이 필요한 경우, long term (stable cell line) 실험이 필요한 경우

http://www.sigmaaldrich.com/Area_of_Interest/Life_Science/Functional_Genomics_and_RNAi.html

 

* 관련정보 : The RNAi Consortium of Broad Institute 홈페이지( http://www.broad.mit.edu/rnai/trc )
=> http://www.sigmaaldrich.com/yfg (내가 원하는 shRNA 검색)
=> http://www.sial.co.kr/rnai (TRC shRNA의 국내 공급 및 구매정보)

 

Knockout / Knockdown
- Knockout이란 용어는 "knockout mouse" 특정 유전자의 DNA를 직접 deletion/disruption함으로써 그 유전자의 발현을
100%억제하는 경우

- Knockdown은 일반적으로 RNAi efficiency를 말할 경우로 RNAi의 경우는 특정유전자의 DNA가 아닌 mRNA를 그 타겟으로하기때문에 원하는 유전자 발현을 100% 억제가 아닌 70-80%내외로 down regulation