Posts Tagged "Gene Expression"
RNA Interference
RNA interference (RNAi) or double-stranded RNA (dsRNA) is a system within living cells that helps to control which genes are active and how active they are. siRNAs were first discovered by David Baulcombe’s group in Norwich, England, as part of post-transcriptional gene silencing (PTGS) in plants1 and later independently identified in wide variety of eukaryotic organisms. These dsRNAs are rapidly processed into short RNA duplexes of 21 to 28 nucleotides in length, which then guide the recognition and ultimately the cleavage of complementary single-stranded RNAs, such as messenger RNAs or viral genomic/antigenomic RNA (Fig. 1). According to their origin or function, naturally occurring small RNA have been described: short interfering RNAs (siRNA), repeat-associated short interfering RNA (rasiRNA or shRNA) and microRNA (miRNA). RNA interference has many biological functions – it is a vital part of the immune response against viruses and also downregulates gene expression by transcriptional silencing of genes or upregulates promoting by RNA activation. Finally, artificial introduction of long dsRNA or siRNA has been adopted as a tool to inactivate gene expression, both in cultured cells and in living organisms.http://www.biosyn.com/TEWdetail.aspx?TEWid=180
A biochemical understanding of the RNAi pathway was crucial to realizing that dsRNAs shorter than 30 base pairs (bp) could be used to trigger an RNAi response in mammals. Tuschl and colleagues showed that transfection of mammalian cells with short RNAs could induce the sequence-specific RNAi pathway, and so overcame the barrier to the use of RNAi as a genetic tool in mammals2. The impetus to use siRNAs and other small RNAs in mammalian cells also came from the long-standing view that protein kinase receptor (PKR) activation3 and similar responses were not effectively triggered by short dsRNAs. Following the initial reports, it took a remarkably short period of time for siRNAs triggers to be adopted as a standard component of the molecular biology toolkit. siRNAs can be introduced into mammalian cells using a variety of standard transfection methods. The strength and duration of the silencing response is determined by several factors: on a population basis, the silencing response is affected mainly by the overall efficiency of transfection, which can be addressed by optimizing conditions. In each cell, silencing depends on the amount of siRNA that is delivered and on the potential of each siRNA to suppress its target, or its potency. Even a relatively impotent siRNA can silence its target provided that sufficient quantities of the siRNA are delivered. However, essentially ‘forcing’ the system by delivering large amounts of reagent is likely to lead to numerous undesired effects.
” title=”http://www.biosyn.com
” target=”_blank”>www.biosyn.com
Bio-Synthesis Inc. a leading provider for Custom Antibody, Custom Peptide Synthesis, Custom siRNA Synthesis, Organic Laboratory Technique, Antibiotic Peptides.
Biotechnology -rna Genes
messenger RNA (mRNA) is generated in order to be translated into protein, numerous classes of “noncoding” RNAs also exist; these complex molecules all share the property of being nontranslatable. The classic categories of noncoding RNAs include ribosomal RNA and transfer RNA, both of which are involved in the translation process.
ver the past decade RNA interference (RNAi) has emerged as a natural mechanism for silencing gene expression. This ancient cellular antiviral response can be exploited to allow specific inhibition of the function of any chosen target gene. RNAi is proving to be an invaluable research tool, allowing much more rapid characterization of the function of known genes. More importantly, RNAi technology considerably bolsters functional genomics to aid in the identification of novel genes involved in disease processes. This review briefly describes the molecular principles underlying the biology of RNAi phenomenon and discusses the main technical issues regarding optimization of RNAi experimental design.
RNAi is a mechanism in molecular biology where the presence of certain fragments of double-stranded RNA (dsRNA) interferes with the expression of a particular gene which shares a similar sequence with the dsRNA.
This study defines the dollar volume of sales, both worldwide and in the U.S., and analyzes the factors that influence market size and growth for RNAi testing. The main objectives of this study are to:
1) understand the different sectors of RNAi testing market and to look at a description of the instruments, reagents and supplies marketed by major companies in each segment;
2) obtain a complete understanding of the individual RNAi-testing platforms-from basic principles to clinical applications;
3) discover feasible market opportunities by identifying high-growth applications in different analytical diagnostic areas, with a focus on the biggest and expanding markets;
4) focus on global industry developments and trends through an in-depth analysis of the major world markets for RNAi measurement technology, including growth forecasts; and
5) present market figures related to the current value of RNAi testing, market projections, market share, key players and sector growth rates.
Read more: biotechnology-online.blogspot.com
Reference: findarticles, Market Wire
, Internal Medicine News
RNAi Medicine
Click for Vacation Video
Welcome to RNAi Medicine. RNA interference (RNAi) is a system within living cells that helps to control which genes are active and how active they are. Two types of small RNA molecules – microRNA (miRNA) and small interfering RNA (siRNA) – are central to RNA interference. RNAs are the direct products of genes, and these small RNAs can bind to specific other RNAs and either increase or decrease their activity, for example by preventing a messenger RNA from producing a protein. RNA interference has an important role in defending cells against parasitic genes, as well as gene expression in general. Therein lies the medical promise of RNAI Medicine.
Brief Interruption. Need a Vacation? Click here…
Among the first applications via RNAi to reach clinical trials are the treatment of macular degeneration and a particular respiratory syncytial virus. RNA interference is also often seen as a promising way to treat cancer by silencing genes differentially upregulated in tumor cells or genes involved in cell division.
Thank you for visiting and bookmarking RNAiMedicine.com. 
RNAi Medicine is your portal for RNAi videos, rnai articles, and general conversation about RNA interference and genetic therapies.
Video
How Short Is Short In Rnai Research
The original work of Mello and Fire from the Univ. of Massachusetts demonstrated in C. elegans, that gene expression is controlled by RNA interference (RNAi) . The initial patent applications filed by the Univ. of Massachussetts, with both Mello and Fire as the inventors, and covering this use of RNAi, clained only dsRNA longer than 25 bp’s. Later on, work done in mamalians showed that the long ds RNA was capable of inducing the release of IFN and other pro-inflammatory cytokines, causing dangerous reactions in the animals we tested. We now know that long dsRNA is recognized in the endosomes by TLRs, inducing an undesirable immune response in the animals; a situation that created a new challenge in the study of RNAi. Subsequently other researchers, such as Tuschl et.al. now at Rockefeller Univ, realized that shorter dsRNAi fragments of 25bp of smaller, while still capable of inhibiting the expression of a targeted gene, failed to induce an innate immunity response. In other words, the mammalian system is still capable of utilizing the diced dsRNA produced by the enzyme Dicer, which normally chops down the long dsRNA to sizes of 21-23 nts with 2 bases overhanging at the 3’ends of each strand. These 2 bases overhanging in dsRNA suggests that perhaps Dicer cleaves the long dsRNA in a fashion analogous to restriction enzymes. This short dsRNA can then interact with the RISC complex, where the guide strand is prepared and readied up to base pair with the target mRNA for its cleavage.
The RNAi situation is a good example of the unexpected in science. Although at the time of the initial discovery it was hard to predict that very small fragments of RNA could be pivotal in such important newly found mechanism, currently, even shorter dsRNA fragments, e.g. 15-18 bps’ are being tested. These new third generation modifiers such as LNA’s, UNA’s and others, because of their size have significant therapeutic potential.
There is a significant amount of ongoing research to elucidate the fine details of this novel gene control mechanism, including but not limited to studies of how miRNA precursors are transported to specific compartments of the cell, as these events may play important roles in the processing of the precursor by Dicer to render the active mature form of dsRNA.
url: www.biosyn.com
site_owner: Jessica Castro
address: 612 E. Main street
city: Lewiville
state: Texas
country: USA
postal_code: 75057
phone_number: 972-420-8505