Collection: Gene Expression, Editing & Transfection

Both place the gene of interest under a tetracycline-responsive promoter, but the transactivator differs. Tet-Off uses tTA, which drives transcription until doxycycline is added — the drug switches expression off. Tet-On uses the reverse transactivator rtTA, which binds the promoter only when doxycycline is present — the drug switches expression on, and the level can be tuned by adjusting the dose.

Leaky basal expression comes from the transactivator and promoter pairing rather than from the cells. Tet-On 3G was engineered around this problem: Takara reports 5- to 20-fold lower basal expression than the earlier Tet-On and Tet-On Advanced systems, together with greater doxycycline sensitivity. The higher sensitivity also matters in vivo, in tissues where high Dox concentrations are difficult to reach, such as the brain.

Transfection delivers naked nucleic acid using a chemical carrier and is straightforward in robust dividing lines such as HEK293 or HeLa. Transduction packages the construct into a viral particle and is the practical route into primary cells, suspension cells and stable integration. If your target resists polymer or lipid delivery, plan a lentiviral vector instead — our Viral Vectors & Reporter Systems category covers that side.

Xfect Transfection Reagent is the plasmid-focused biodegradable polymer, with a single-tube protocol that works in serum and needs no optimization of plasmid-to-polymer ratio. Xfect RNA delivers mRNA, siRNA, sgRNA and microRNA by forming biodegradable nanoparticles. Xfect Protein uses a cell-penetrating peptide to carry active protein directly into cells, including hard-to-transfect human suspension lines and mouse embryonic stem cells.

Verify at the DNA level before investing in phenotyping. Guide-it plasmid systems co-express Cas9, the target sgRNA and a bright fluorescent protein, so transfected cells can be monitored or sorted, and the Guide-it Mutation Detection Kit then scores indels in the amplified target region. Guides can also be transcribed and tested in vitro against a PCR target fragment before any cell work begins.

The Tet, Guide-it and Xfect lines reach Israeli labs through Danyel Biotech, official Israeli distributor for Takara Bio, including temperature-controlled shipping for sensitive components. Our specialists can also help decide between plasmid, lentiviral and cell-line formats before you order — ask for a quote from this page.