mMESSAGE mMACHINE® T7 Ultra Kit combines novel cap analogs, anti-reverse cap analogs (ARCA) and Patented high-yield transcription technology to generate RNA transcripts for higher protein yields compared to other transcripts after translation. Advantages of mMESSAGE mMACHINE® T7 Ultra Kit:

•Synthesize more protein from in vitro transcribed RNA
•Available in both in vitro and Express RNA transcripts more efficiently in vivo
• Stabilize in vivo transcripts with the included polyA tail reagent

ARCA Plus Cap RNA is more translationally active
The base modifications in ARCA cause it to be incorporated only in functional, translatable orientations; whereas traditional cap analogues are incorporated in both functional and non-functional orientations Both directions. Therefore, incorporation of ARCA into the transcription reaction results in 100% translatable capped RNA. This is further enhanced by the addition of a poly(A) tail to the mMESSAGE mMACHINE® T7 Ultra transcript. Experiments comparing ARCA and ARCA/polyA tail transcripts to cap analogue and cap analogue/polyA tail transcripts showed that protein synthesis levels were higher when using ARCA capped RNA.

What is ARCA?
ARCA is a modified cap analogue in which the 3' OH group (close to m⁷G) is replaced by OCH₃ (see schematic ). Because of this substitution, RNA polymerase can only use the remaining hydroxyl group to initiate transcription, forcing ARCA to be incorporated in the forward direction. Therefore, transcripts synthesized with ARCA at the 5' end are 100% translatable, resulting in a strong stimulatory effect on translation.

Proper capping of in vitro transcribed RNA
Proper capping of RNA promotes proper initiation of protein synthesis and in vivo mRNA stability and processing. Uncapped RNA is rapidly degraded by cellular RNase after microinjection or transfection into cells. Capped RNAs are generally more efficiently translated in in vitro translation systems, producing RNAs with cap analogues incorporated only in a functional orientation. Therefore, replacing traditional cap analogues with ARCA guarantees the synthesis of 100% translatable capped RNA.