Go Back   Science Forums Biology Forum Molecular Biology Forum Physics Chemistry Forum > Molecular Research Topics Forum > RNA Techniques Forum > RNAi and SiRNA Forum
Register Search Today's Posts Mark Forums Read

RNAi and SiRNA Forum Discuss and Post Questions in this forum about RNA interference and siRNA. RNAi and siRNA transfection, inhibition of endogenous genes, and miRNA and shRNA.


RNAi

RNAi - RNAi and SiRNA Forum

RNAi - Discuss and Post Questions in this forum about RNA interference and siRNA. RNAi and siRNA transfection, inhibition of endogenous genes, and miRNA and shRNA.


Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 06-14-2006, 04:41 PM
aftabac's Avatar
Nobel Laureate
 
Join Date: Jun 2006
Location: Pakistan
Posts: 570
Thanks: 5
Thanked 41 Times in 34 Posts
Default RNAi



RNAi technology based on Double stranded RNA or dsRNA, who naturally dsRNA is encoded in the genome, is it possible other then shRNA.
I hope you will answer.


waiting

Aftab ahmad chatha
[Only registered users see links. ]
Reply With Quote
  #2  
Old 06-15-2006, 09:24 PM
Polyzoom's Avatar
Pipette Filler
Points: 1,993, Level: 27 Points: 1,993, Level: 27 Points: 1,993, Level: 27
Activity: 0% Activity: 0% Activity: 0%
 
Join Date: Jun 2006
Posts: 5
Thanks: 0
Thanked 0 Times in 0 Posts
Default Re: RNAi

I know there are:

miRNA - micro-RNA, a form of ss single-stranded RNA typically 20-25 nucleotides

shRNA - short hairpin RNA (double stranded in hairpin elements)

siRNA - siRNA have short around 20-nucleotide double-strand of RNA (dsRNA) with 2-nt 3' overhangs

shRNA = siRNA they are the same I believe

(RNAi molecules)

miRNA, siRNA, and shRNA are all found in humans. I am not sure about any newer forms of inhibitory RNA molecules.
Reply With Quote
  #3  
Old 06-15-2006, 09:26 PM
Polyzoom's Avatar
Pipette Filler
Points: 1,993, Level: 27 Points: 1,993, Level: 27 Points: 1,993, Level: 27
Activity: 0% Activity: 0% Activity: 0%
 
Join Date: Jun 2006
Posts: 5
Thanks: 0
Thanked 0 Times in 0 Posts
Lightbulb Re: RNAi

oh there are also larger dsRNAs which are precursor molecules to siRNA / shRNAs

Reply With Quote
  #4  
Old 06-16-2006, 04:30 AM
aftabac's Avatar
Nobel Laureate
 
Join Date: Jun 2006
Location: Pakistan
Posts: 570
Thanks: 5
Thanked 41 Times in 34 Posts
Default Re: RNAi

yes all these RNA forms are present in the human, but i want to know how these dsRNA are encoded by the genome. or how these are formed in humans.

aftab
Reply With Quote
  #5  
Old 06-19-2006, 07:02 PM
admin's Avatar
Administrator
 
Join Date: Nov 2005
Posts: 1,418
Thanks: 883
Thanked 68 Times in 58 Posts
Default Re: RNAi

Here is a nature review paper on RNAi

http://www.nature.com/nature/journal...C32422287EA5DE

Figure 1 | RNAi-mediated gene silencing.
RNA interference (RNAi) is an apparently ancient defence mechanism against foreign double-stranded RNA (dsRNA). RNAs of just 22 nucleotides in length, called small interfering RNAs (siRNAs), are snipped from longer dsRNA chains by an enzyme called Dicer. The antisense strand of the siRNA is used by an RNA-induced silencing complex (RISC) to guide messenger RNA (mRNA) cleavage, so promoting mRNA degradation.
Modified with permission from McManus, M. T. & Sharp, P. A. Gene silencing in mammals by small interfering RNAs. Nature Rev. Genet. 3, 737-747 (2002) © Macmillian Magazines Ltd. miRNA, microRNA; stRNA, small temporal RNA.
[IMG]file:///E:/DOCUME%7E1/GUS%7E1.GUS/LOCALS%7E1/Temp/moz-screenshot.jpg[/IMG][IMG]file:///E:/DOCUME%7E1/GUS%7E1.GUS/LOCALS%7E1/Temp/moz-screenshot-1.jpg[/IMG][IMG]file:///E:/DOCUME%7E1/GUS%7E1.GUS/LOCALS%7E1/Temp/moz-screenshot-2.jpg[/IMG]http://www.nature.com/horizon/rna/ba...ference_f1.jpg

Interestingly, the human siRNAs are there to protect against dsRNAs from viruses, however they THEMSELVES are first dsRNAs to begin with...



Some Interesting Articles in:
Specific inhibition of gene expression by small double-stranded RNAs in invertebrate and vertebrate systems

Natasha J. Caplen*,, Susan Parrish,§, Farhad Imani¶, Andrew Fire, and Richard A. Morgan*,
PNAS | August 14, 2001 | vol. 98 | no. 17 | 9742-9747

Short interfering RNAs (siRNAs) are double-stranded RNAs of 21-25 nucleotides that have been shown to function as key intermediaries in triggering sequence-specific RNA degradation during posttranscriptional gene silencing in plants and RNA interference in invertebrates. siRNAs have a characteristic structure, with 5'-phosphate/3'-hydroxyl ends and a 2-base 3' overhang on each strand of the duplex. In this study, we present data that synthetic siRNAs can induce gene-specific inhibition of expression in Caenorhabditis elegans and in cell lines from humans and mice. In each case, the interference by siRNAs was superior to the inhibition of gene expression mediated by single-stranded antisense oligonucleotides. The siRNAs seem to avoid the well documented nonspecific effects triggered by longer double-stranded RNAs in mammalian cells. These observations may open a path toward the use of siRNAs as a reverse genetic and therapeutic tool in mammalian cells.
Reply With Quote
Reply

Tags
rnai


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Lecture Return to the RNAi World Rethinking Gene Expression and Evolution Video admin RNAi and SiRNA Forum 0 02-10-2008 10:40 AM
Questions on plant RNAi Dr. James J. Campanella Protocols and Methods Forum 0 08-29-2007 01:55 PM
Questions on plant RNAi Dr. James J. Campanella Arabidopsis and Plant Biology 0 08-29-2007 01:55 PM
RNAi scoops medical Nobel aftabac General Science Questions and Layperson Board 2 10-03-2006 11:09 PM
The insulating role of an RNAi architect aftabac RNAi and SiRNA Forum 1 09-25-2006 08:36 AM


All times are GMT. The time now is 01:55 PM.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright 2005 - 2012 Molecular Station | All Rights Reserved
Page generated in 0.14926 seconds with 16 queries