Small interfering RNA (siRNA) or silencing RNA is used in the gene silencing technique to suppress gene expression. It was discovered that break down of viral RNA can produce siRNA molecules. siRNAs are similar to mRNA molecule function in terms of acting as a signal transmitter from one cellular substructure to another, and can target specific mRNA regions in a sequence-specific manner to decrease transcription (gene transcription process involve genetic information literally copied from DNA to RNA, followed by translation process where RNA code used to produce proteins).

MicroRNA molecules (miRNA) naturally occur in cells as a component of the post-transcriptional gene silencing (PTGS) apparatus. Soon after discovery of miRNA regulatory function, scientists began using siRNAs and miRNAs to study gene expression utilizing this gene silencing technology.

Performing RNAi in invertebrates is reasonably easy because a simple transfection of long a dsRNA is enough to degrade the target mRNA. Vertebrate cells elicit a significant antiviral response when they detect the presence of a long dsRNA. Consequently, instead of knocking down the identified gene, the cell goes through apoptosis giving entirely undesirable results.

Commercial siRNA transfection services are offered by biology CRO Altogen Labs (www.altogenlabs.com)

Scientists have solved the problem of antiviral response by utilizing small-sized siRNA. They are created by segmenting a long dsRNA. When generated appropriately synthetic siRNA are potent gene silencers, do not produce any significant antiviral response and exhibit remarkable specificity to the target mRNA. Researchers develop siRNA from long dsRNA by dicing small hairpin RNAs or long dsRNA sequences, which in effect is an RNase III family endoribonuclease enzyme. The dicer cuts a dsRNA into smaller siRNA segments that usually ends with two base overhang .

siRNAs are often introduced in cell lines either through transfection or electroporation. Soon after being inserted in the host cell, siRNA molecules become a part of the RNA-induced silencing complex (RISC). Guided by the antisense strand of the siRNA, RISC degrades the targeted mRNA inhibiting its translation. Appropriate assays are then performed to detect and gauge RNAi activity. Controls are normally set up so RNAi results can be properly compared.

The success of RNAi is dependant on correct delivery of siRNA in appropriate amount at a time when it will brings about the maximum expected response. Such precision can be tricky. Off-targeting by siRNAs proves lethal and poses analytical issues at times. Researchers are looking for better ways of designing and delivering siRNA. The excellent response of siRNAs has impelled many organizations to market gene specific predesigned kits to help researchers. About 3-5 siRNAs per gene are needed to have a potent RNAi effect . The consequent dollar intensive nature of this technology dissuades many laboratories from exploiting its true potential. Efforts are on to develop innovative yet reasonably affordable in vitro generation of siRNAs. Animal (In Vivo) RNAi transfection kits are offered by Altogen Biosystems (www.altogen.com).

siRNA helps scientists to knockdown expressions of a target gene. This is done to have a superior understanding about the functions of the knocked down genes. They help understand the complex pathways genes that eventually will help develop effective treatments for many lethal diseases including cancer, autoimmune discrepancy, viral infections, Huntington disease and degenerative conditions.

Medical researchers, geneticists, and research laboratories utilize customized siRNA designs capable of silencing specific genes or specific genes under study. siRNA design service provides a number of options for those requiring construct builders, sequence scrambles as well as genome wide design and screening options (f.e. Altogen Labs provides siRNA design, synthesis, and screening services). Molecular biological services focus on providing researchers, laboratories, and those overseeing clinical trials with increased efficacy rating for knockdown.

siRNA construct builders create the small, hairpin type inserts utilized from siRNA targets for expression vectors, as well as the provision of analysis and calculations that are targeted or literally customized to a user’s specific requirements. siRNA sequence scrambler services provide negative controls for experiments utilizing siRNA, creating scrambled sequences that are identical in nucleotide composition for input sequences, and that pass the same type of filtering processes. The least possible number of matches with mRNA or messenger RNA of particular organisms are also available through siRNA sequence scramblers, offering researchers thousands of combinations and options for study. Such capabilities provide researchers the option of testing and analyzing a number of siRNA processes when it comes to knockdown capabilities, especially for comparison.

A siRNA design service may also provide numerous genomes, in mouse, rat, and human genes. Gene pools (siRNA libraries) offer over 80,000 variations, with such designs saving and maximizing not only time but also optimal experiment results. The availability of such massive numbers of gene pools and their variations allow greater research capabilities and access to experiments than would be available otherwise. When it comes to siRNA design, algorithms can and often include assessment for specifically desired sequences, thermodynamic properties, secondary structures, and so forth.

siRNA design services basically customize siRNA to meet the needs of the researcher experimenting, accessing or analyzing RNA interference, enabling to select specific siRNA sequences that are optimal to targeted gene expression. Optimal siRNA design platforms are made available by the careful documentation of strategies in the design of effective siRNA sequences, ensuring capability of interfacing customized design siRNA for specific gene targeting in a number of fields including life sciences and biomanufacturing. siRNA design companies focus on developing comprehensive services that allow users access to customize siRNA design platforms that offer as much as 80% gene silencing capabilities. Such accessibility is utilized in the study of genomics, proteomics and by manufacturing products and services.