Minicircle DNA Vector Technology: Non-Integrative Sustained Expression
• Sustained expression over weeks
• No integration into the genome
• Optimized E. coli production strain
• Works in vitro and in vivo

Minicircles are episomal DNA vectors that are produced as circular expression cassettes devoid of any bacterial plasmid DNA backbone. Their smaller molecular size enables more efficient transfections and offers sustained expression over a period of weeks as compared to standard plasmid vectors that only work for a few days. For dividing cells, expression of the minicircles lasts up to 14 days. For non-dividing cells, expression of the minicircles drops slightly after the first week, but then can continue to express the transgenes for months.
Multiple minicircle vector formats with different promoters and fluorescent reporters developed by SBI are offered, see table below.

Production of minicircle DNA


The Minicircle (MC) DNA elements are generated by intramolecular (cis-) recombination from a parental plasmid (PP) mediated by PhiC31 integrase. The full-size MC-DNA construct is grown in a special host E. coli bacterial strain ZYCY10P3S2T harboring an Arabinose-inducible system to express PhiC31 integrase and I-SceI endonuclease simultaneously.
Adding arabinose to the media turns on the integrase and endonuclease genes. The PhiC31 integrase produces the MCDNA molecules as well as PP-DNA backbone from the full-size MC-DNA construct. The Sce-I endonuclease then degrades the PP-DNA backbone preventing immune responses.


It is highly recommended to use the MC-Easy Minicircle DNA Production Kit, which contains the following optimized reagents for perfect Minicircle DNA preparations:

• ZYCY10P3S2T Minicircle DNA Producer Strain, 5 vials of competent cells
• 5X Minicircle Growth medium (200 ml)
• 10X Induction Medium (100 ml)
• Minicircle DNA Re-Purification Kit (5 preps) incl. Minicircle-safe DNAse, buffers, and Purification/Concentration columns 
• MC-Fection Minicircle DNA Transfection Reagent (100 ul)

The kit is also available in a version without E. coli producer cells.
The E. coli producer cells are also available as a separate product.


Minicircle DNA Vector Options

SBI has created a set of minicircle parental cloning vector formats to choose from. Select from CMV or EF1a promoters, GFP, RFP and Puro markers. The minicircle parental cloning shRNA vector formats feature either CMV or EF1a expressing the markers and a downstream H1 promoter to express high levels of the cloned shRNA sequence. See the table below for the particular MCS cloning sites for each of the minicircle DNA vectors.





Parental minicircle plasmids and the ZYCY10P3S2T Producer Bacterial Strain are available for purchase by not-for-profit researchers only. Commercial users may purchase pre-made mcDNA [ready-to-transfect] only. SBI also offers custom parental plasmid cloning and mcDNA production to both not-for-profit and commercial end users. Please contact us for additional details by using the link below. For buying the parental MC production system, commercial users should contact BioCat for further information by using the link below.



Minicircle Parental Vector without Promoter, Multiple Cloning Site Version 2: pMC.BESPX-MCS2