miRNA is the inherent gene silencing machinery which can have more than one mRNA target, whereas siRNA can be designed to target a particular mRNA target. By design, both siRNA and miRNA are 20-25 nucleotides in length. The target sequence for siRNAs is usually located within the open reading frame, between 50 and 100 nucleotides downstream of the start codon. There are two ways in which cells can be transfected with desired RNAi: 1. Direct transfection (with calcium phosphate co-precipitation or cationic lipid mediated transfection using lipofectamine or oligofectamine), and 2. Making RNAi lentiviral constructs (followed by transformation and transduction). Lentiviral constructs are time consuming, but provide a more permanent expression of RNAi in the cells, and consistent gene silencing. Direct transfection of oligonucleotides provides temporary genetic suppression. Traditional methods like calcium phosphate co-precipitation have challenges like low efficiency, poor reproducibility and cell toxicity. Whereas, cationic lipid-based transfection reagents are able to overcome these challenges, along with applicability to a large variety of eukaryotic cell lines. When using oligos, the ideal concentration lies between 10-50nM for effective transfection.
When extracting nucleic acids from cell cultures, thorough homogenization of cells via vortexing in lysis buffer is very necessary. Choose the best RNA isolation method keeping in mind the downstream applications, generally, column-based isolations result in clean and concentrated RNA samples. Downstream applications like sequencing and cDNA synthesis require high-quality RNA, always treat the samples with DNases and check their integrity by running a gel.
Get tips on using pcDNA™3.1 (+) Mammalian Expression Vector to perform siRNA / miRNA gene silencing Human - U251 cofilin-1 (CFL1)
Get tips on using BioPrime™ Array CGH Genomic Labeling Module to perform Microarray Comperative genomic hybridization - Human PBMCs
I would like to regulate the expression of a gene and in order to do that, I have purchased specific siRNA. After optimizing my transfection protocol and using electroporation I have achieved a 60-70% reduction of the gene of interest. However, I cannot observe a significant reduction of mRNA expression but only a reduction of protein. What might be the problem? Could the problem be in my cell treatment method?
Site-directed mutagenesis (SDM) can be challenging, particularly during detection/confirmation of (SDM) in colonies by sequencing or PCR techniques. This common issue in SDM is heavily relying on designing of mutagenic primer pairs. The best solution is to design the mutagenic primers that have extended 3'-ends/3'-overhang. This would provide the annealing region between the mutagenic primer pair is essentially shorter. and hence ensure a lower annealing temperature for the primer pair along with a higher chance of annealing to the template.
Get tips on using NAPSIN A (TMU-AD02) ANTI-HUMAN MOUSE IGG MOAB to perform Immunohistochemistry Human - Naspsin A
Get tips on using Control siRNA-A to perform siRNA / miRNA gene silencing Human - OV2008 Yap Gene Lipofectamine
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