BLOCK-iT™ Pol II miR-CLK1 Validated miRNA DuoPak - FAQs

The BLOCK-iT miR RNAi expression system allows you to take advantage of promoter flexibility by choosing from a variety of Pol II promoters like CMV, Ubc, tissue specific, or inducible promoters. The miRNA vectors also allow you to clone multiple sequences in the same vector, thereby enabling you to target more than one gene or more than one location in a gene using a single plasmid. An additional advantage offered by some of the miRNA expression vectors is that transfection efficiency can be monitored with the EmGFP fusion partner.

Find additional tips, troubleshooting help, and resources within our RNAi Support Center.

Yes. The miRNA cloning vectors are designed such that you can easily chain together multiple miRNAs to express them in one transcript. This can be used to increase transcription levels of the same miRNA sequence, or to combine multiple different sequences in one co-cistronic expression cassette.

Yes. The miR miRNA vectors are Gateway cloning compatible, and you could use Gateway cloning to transfer the miR miRNA expression cassette to any of our Gateway-adapted viral expression vectors.

The miRNA vectors use endogenous miRNA processing machinery to allow targeted RNAi knockdown of specific genes, but they are not tested for use in the analysis of endogenous miRNA. Endogenous miRNAs are typically not 100% homologous to their targets and thus invoke translational suppression. Our products are designed with 100% homology to the target gene and generally result in target mRNA cleavage.

Both systems are used for gene targeting or gene knockdown but each has distinctive features. The shRNA expression vectors like pENTR/U6 or pENTR/H1-TO use Pol III promoters, whereas the miRNA expression vectors are flexible to use more common and more processive Pol II promoters like CMV, EF1 or other mammalian expression promoters. You can only clone a single shRNA sequence into an shRNA vector to target a single gene, whereas multiple miRNA sequences can be cloned together into an miRNA vector to target one or more genes, or multiple locations in a gene. An additional feature of the miRNA expression vectors is that, due to use of Pol II promoters, the miRNA can be expressed directly in fusion with a reporter gene like EmGFP to monitor transfection and transcription.

Find additional tips, troubleshooting help, and resources within our RNAi Support Center.

All the BLOCK-iT miR RNAi expression vectors are Gateway-adapted and contain the CMV promoter. If more specialized expression is required with a different promoter, the miRNA vectors allow for easy recombination with any other suitable destination vector that Thermo Fisher Scientific offers. A wide variety of Gateway Destination vectors that contain promoters such as EF-1apha or Ubc are available, and all be used for miRNA expression. MultiSite Gateway Technology vectors are also available which will enable you to use a tissue-specific promoter or a promoter of your choice to express miRNA.