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Tuesday, December 20, 2011

Interference RNA (RNAi),siRNA Transfection, Antisense RNA Technology methods & applications.


Anti Sense RNA
During mRNA synthesis DNA strand is transcribed to give messenge RNA (mRNA) and this messenger RNA is called as a sense RNA Anti Sense RNA is a short single stranded RNA which can bind the the complementary messenger RNA(mRNA) which is transcribed by the specific gene with in the cell. The binding of the anti sense RNA to the mRNA prevents it from reaching the ribosome for translation.
Antisense RNA Technology
Anti sense RNA drugs are small chemically modified nucleotides which are complementary to its target RNA. Once it is introduced into the cell results in RNA Introduction of antisense RNA into the cell results in the formation of RNA-DNA hybrid, this hybrid will be degraded by RNase H and there by preventing the translation of the that particular mRNA ultimately resulting in gene silencing. Blocking the disease causing protein production has can results in improvement in the treatment of certain disease which otherwise would be difficult to treat using normal methods.
Antisense RNA technology has application in agricultural field also, this technology was used to develop Flavr Savr Tomato which offered improved Flavor and shelf life by delaying the ripening process.

Regulus Therapeutics Inc. is a bio-pharmaceutical company focused on the development of microRNA(miRNA) based drugs targeting fibrosis, metabolism and cardiovascular diseases, cancer, HCV and immune-related diseases.
RNA interference (RNAi) is the process of regulation of genes in the cell. The other names for RNA interference are post translation gene silencing, co-suppression, quelling etc.
RNA interefernce is caused by two types of RNA molecules siRNA – small interference RNA and miRNA – micro RNA. Interference RNA works by targeting RNA induced silencing complex (RISC) to bind and degrade the mRNA.

siRNA Mechanism

Antisense RNA Technology
siRNA Mechanism


Interference RNA (RNAi) Applications
One of the promising application of interference RNA (RNAi) technology is for the treatment of viral infection. stem cells are used as a model for RNAi studies for better understanding of molecular regulations with in the cell.
Study of various gene regulation pathways and associated disease progress.
Si RNA Transfection:
Transfection is the process of introduction of foreign DNA, RNA, or protein molecules into eukaryotic cells. Transfection can be Transient or Stable. In Transient transfection the transfected molecule will only be expressed for a short period of time.
Methods of siRNA Transfection
Physical and chemical methods can be used to transfer DNA/RNA (siRNA) into the cell. Even bacterial and viral methods are also used.
Physical methods involves electroporation, microinjection, sono-poration, impalefection, optical transfection, etc.
Use of calcium phosphate method, liposomes, Polymers etc comes under the chemical means of Transfection.

References
RNA Interference: Applications in Vertebrates, Frederic Bushman
interference RNA, Wikipedia
Application of RNA interference to study stem cell function: current status and future perspectives,
Gang-Ming Zou1 and Mervin C. Yoder