Esirna
Encyclopedia
esiRNA or Endoribonuclease-prepared siRNAs are a mixture of siRNA
oligo
s resulting from cleavage of long double-stranded RNA (dsRNA) with an endoribonuclease such as Escherichia coli RNase III
or dicer
.
An alternative concept to the usage of chemically synthesized siRNA
for RNA Interference
(RNAi
) is the enzymatic digestion of long double stranded RNAs in vitro. In this case a cDNA template is amplified by PCR and tagged with two bacteriophage-promotor sequences. RNA polymerase
is then used to generate long double stranded RNA that is homologous to the target-gene cDNA. This RNA is subsequently digested with RNase III
from Escherichia coli
to generated short overlapping fragments of siRNAs with a length between 18-25 base pairs. This complex mixture of short double stranded RNAs is similar to the mixture generated by Dicer
cleavage in vivo and is therefore called endoribonuclease-prepared siRNA or short esiRNA. esiRNA are a heterogeneous mixture of siRNAs that all target the same mRNA sequence. These multiple silencing triggers lead to highly specific and effective gene silencing.
Sírna
Sírna Sáeglach , son of Dian mac Demal, son of Demal mac Rothechtaid, son of Rothechtaid mac Main, was, according to medieval Irish legend and historical tradition, a High King of Ireland...
oligo
Oligonucleotide
An oligonucleotide is a short nucleic acid polymer, typically with fifty or fewer bases. Although they can be formed by bond cleavage of longer segments, they are now more commonly synthesized, in a sequence-specific manner, from individual nucleoside phosphoramidites...
s resulting from cleavage of long double-stranded RNA (dsRNA) with an endoribonuclease such as Escherichia coli RNase III
RNase III
RNase III enzymes specifically bind to and cleave double-stranded RNA . There are three subdivisions, known as Class 1, 2, and 3.Prokaryotic ribonuclease III is an enzyme that digests double-stranded RNA. It is involved in the processing of ribosomal RNA precursors and of some mRNAs.* Class 1...
or dicer
Dicer
Dicer is an endoribonuclease in the RNase III family that cleaves double-stranded RNA and pre-microRNA into short double-stranded RNA fragments called small interfering RNA about 20-25 nucleotides long, usually with a two-base overhang on the 3' end...
.
An alternative concept to the usage of chemically synthesized siRNA
Sírna
Sírna Sáeglach , son of Dian mac Demal, son of Demal mac Rothechtaid, son of Rothechtaid mac Main, was, according to medieval Irish legend and historical tradition, a High King of Ireland...
for RNA Interference
RNA interference
RNA interference is a process within living cells that moderates the activity of their genes. Historically, it was known by other names, including co-suppression, post transcriptional gene silencing , and quelling. Only after these apparently unrelated processes were fully understood did it become...
(RNAi
RNAI
RNAI is a non-coding RNA that is an antisense repressor of the replication of some E. coli plasmids, including ColE1. Plasmid replication is usually initiated by RNAII, which acts as a primer by binding to its template DNA. The complementary RNAI binds RNAII prohibiting it from its initiation role...
) is the enzymatic digestion of long double stranded RNAs in vitro. In this case a cDNA template is amplified by PCR and tagged with two bacteriophage-promotor sequences. RNA polymerase
RNA polymerase
RNA polymerase is an enzyme that produces RNA. In cells, RNAP is needed for constructing RNA chains from DNA genes as templates, a process called transcription. RNA polymerase enzymes are essential to life and are found in all organisms and many viruses...
is then used to generate long double stranded RNA that is homologous to the target-gene cDNA. This RNA is subsequently digested with RNase III
RNase III
RNase III enzymes specifically bind to and cleave double-stranded RNA . There are three subdivisions, known as Class 1, 2, and 3.Prokaryotic ribonuclease III is an enzyme that digests double-stranded RNA. It is involved in the processing of ribosomal RNA precursors and of some mRNAs.* Class 1...
from Escherichia coli
Escherichia coli
Escherichia coli is a Gram-negative, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms . Most E. coli strains are harmless, but some serotypes can cause serious food poisoning in humans, and are occasionally responsible for product recalls...
to generated short overlapping fragments of siRNAs with a length between 18-25 base pairs. This complex mixture of short double stranded RNAs is similar to the mixture generated by Dicer
Dicer
Dicer is an endoribonuclease in the RNase III family that cleaves double-stranded RNA and pre-microRNA into short double-stranded RNA fragments called small interfering RNA about 20-25 nucleotides long, usually with a two-base overhang on the 3' end...
cleavage in vivo and is therefore called endoribonuclease-prepared siRNA or short esiRNA. esiRNA are a heterogeneous mixture of siRNAs that all target the same mRNA sequence. These multiple silencing triggers lead to highly specific and effective gene silencing.