Bicistronic or Internal Ribosome Entry Site (IRES) Element — Efficient co-expression of two genes in a single vector

The IRES element is exactly what's needed for certain experiments when a single-gene vector falls short. IRES enables the coordinated co-expression of two genes with the same vector. For example, you can monitor the delivery of one gene by using a second gene with a fluorescent tag or express a protein of interest and simultaneously biotinylate it with the same vector. An IRES element is especially useful for gene delivery when working with stem and primary cells and when the following tasks are pursued:

• Monitor gene delivery efficiency
• Monitor protein modification
• In vivo biotinylation
• Stable transfection

Technology

The IRES technology serves a dual-purpose. It allows the coordinated and efficient expression of two genes using the same promoter in a single vector (see figures 1 and 2). Virtually any combination of genes is possible. GeneCopoeia has already developed many constructs.

Combined with OmicsLink expression-ready clones

For a variety of applications, GeneCopoeia has incorporated the IRES element into several mammalian and lentiviral vectors using a wide choice of reporter genes including the following:

• eGFP
• mCherry
• SUMO
• biotin ligase
• neomycin
• luciferase

More than 20,000 human and 15,000 mouse genes are available in CMV promoter driven bicistronic (IRES) expression vectors.

Figure1. OmicsLink™ ORF cDNA expression clones with IRES element in mammalian and lentiviral expression vector systems.

Advantages

• Minimal affect on biological activities of target proteins when co-expressed with reporter/ assaying genes.
• Efficient co-transfection due to coordinated co-expression of two genes from a single expression vector.

Applications

• Monitor gene delivery efficiency by co-expressing proteins with reporter genes including eGFP, mCherry or Luciferase.
• Monitor protein modification by a specific modifier in vivo by co-expressing proteins with protein modifiers such as Sumo.
• In vivo biotinylation of expressed proteins with AviTag by co-expressing with biotin ligase.
• Establish stable transfected cell lines for efficient selection by co-expressing with selection marker genes like Neomycin.

How it works

Figure 2. Specific biotinylation of AviTag eGFP by E. coli biotin ligase in 293 cells

List of expression vectors with IRES technology