Shop All Transcription Kits

MAXIscript™ T3 Transcription Kit (Invitrogen™)

The Ambion® MAXIscript® T3 In Vitro Transcription Kit synthesizes RNA probes in just 10 minutes for use in ribonuclease protection assays, in situ hybridization, and blot hybridizations. Each kit contains sufficient reagents for 30 reactions.


• High yields of high specific activity, full-length RNA probes in just 10 minutes
• Ideal probe synthesis kit for nuclease protection assays, northern and Southern blots, and in situ hybridization
• Includes TURBO DNase™
• All kits contain quality-tested DNase/RNase-free reagents

The MAXIscript® In Vitro Transcription Kit synthesizes RNA probes with specific activities reaching 1 × 109 cpm/µg in just 10 minutes. MAXIscript® Kits are very efficient at synthesizing full-length probes, even at limiting nucleotide concentrations, making them the perfect companion to ribonuclease protection assays. MAXIscript® Kits are also an excellent choice for the synthesis of nonisotopically labeled probes. Labeling can be accomplished post-transcriptionally by using Ambion's BrightStar® Psoralen-Biotin Labeling Kit, or during transcription by incorporating modified nucleotides into the reaction. MAXIscript® Kits can also be used for the synthesis of modest amounts of unlabeled RNA (2–6 µg/20 µl reaction) of up to 2 kb.

Precision gRNA Synthesis Kit (Invitrogen™)

The Precision gRNA Synthesis Kit is a complete system for rapid synthesis of guide RNA (gRNA) ready to complex with TrueCut™ Cas9 Protein v2 for transfection-ready Cas9 protein/gRNA ribonucleoprotein (Cas9 RNP). This Cas9 RNP format, with our TrueCut Cas9 Protein v2, has been tested in a variety of suspension and adherent cell lines with >70% cleavage efficiencies and no indications of toxicity. Starting with two short single-stranded oligos that code for the target sequence, the gRNA template is assembled with a T7 promoter in a short ‘one-pot’ PCR reaction. The assembled product is then used as template in an in vitro transcription (IVT) reaction followed by a rapid purification step, yielding transfection-ready gRNA in as little as four hours. Resulting gRNA can also be co-transfected with our ready-to-transfect Invitrogen™ CRISPR Nuclease mRNA. Both protein and mRNA Cas9 formats require no plasmid manipulation and so are amenable to high throughput and multiplex genome-wide cell engineering approaches.

Features of the Precision gRNA Synthesis Kit include:
• Fast assembly and synthesis of any gRNA target in as little as four hours including template assembly
• High yield (>10 ug) and concentration (>200 ng/uL) of gRNA

How to obtain a gRNA sequence
Genome editing with CRISPR technology requires a noncoding guide RNA (gRNA) in order to cleave genomic DNA at a target sequence of interest. The gRNA has two molecular components: a target-specific CRISPR RNA (crRNA) and a trans-activating crRNA (tracrRNA) that have been combined into one transcript. The target sequence (20 bases) must be immediately upstream of a PAM motif (NGG) which allows the Cas9 to initiate binding. The PAM is only on the target DNA and not part of the target specific CRISPR sequence. The gRNA and the PAM motif guide the Cas9 nuclease to the target genomic sequence to form a complex and create a double-stranded blunt DNA break (DSB) three nucleotides upstream from the PAM site.

Use our CRISPR Search and Design Tool to search our database of >600,000 gRNA sequences specific to every gene in the human and mouse genomes. Invitrogen predesigned gRNAs are optimized for gene knockout and typically target the first three transcribed exons per gene. Search results include recommendations based on minimizing potential off-target effects, potential binding sites, and exon maps with gRNA locations. This tool can also be used to analyze any sequence of interest to design unique CRISPR sequences.

How to make gRNA
Once gRNA sequences have been selected, choose from three options for making gRNA:
1. TrueGuide synthetic guide RNA—choose from our catalog of predesigned gRNAs or upload your sequence to our TrueGuide gRNA Ordering Tool
2. Precision gRNA Synthesis Kit (this page)—for transfection-ready gRNA in as little as four hours including template assembly
3. Genome Engineering Services—save time and effort and have our custom services team design, synthesize, and purify in vitro transcribed (IVT) gRNA sequences for you. To obtain a services quotation, or to order, please contact our Custom Services department at 1-800-955-6288 x45682 or

TranscriptAid T7 High Yield Transcription Kit (Thermo Scientific™)

Thermo Scientific TranscriptAid T7 High Yield Transcription Kit contains reagents for 50 reactions of 20 µL. Each reaction yields up to 200 µg RNA from 1 µg of template in 2 hours. The reaction can be scaled up to produce milligram amounts of full-length RNA. The kit can be used to produce both long and short transcripts for applications that require large yields of RNA. All necessary reagents for transcription are included, as well as the RiboRuler High Range RNA Ladder for sizing and quantification.


Exceptionally high yields—up to 200 µg in 2 hours
Versatile—suitable for both short and long RNA transcripts
Milligram amounts of RNA in a single, scaled-up reaction
Flexible—generates unlabeled, labeled or capped RNA
RiboRuler RNA Ladder supplied with kit for sizing and quantification


In vitro transcription
In vitro translation
• Generation of hybridization probes for:
• microarrays
in situ hybridization
• blotting

• RNase protection assays
• RNA binding protein assays
• Antisense RNA and RNAi
• RNA amplification
• Microinjection studies


• TranscriptAid Enzyme Mix
• 5X TranscriptAid Reaction Buffer
• DNase I, RNase-free
ATP Solution
CTP Solution
GTP Solution
UTP Solution
• Control template
• 3 M Sodium Acetate Solution, pH 5.2
• DEPC-treated Water
• 2X RNA Loading Dye
RiboRuler High Range RNA Ladder, ready-to-use
• 0.5 M EDTA, pH 8.0
• Detailed Protocol

* The improved version of TranscriptAid T7 High Yield Transcription Kit contains Tris-buffered NTPs instead of previously used NTPs titrated with KOH. Usage of Tris-buffered NTPs leads to higher yields of RNA transcripts.

mMESSAGE mMACHINE™ T7 ULTRA Transcription Kit (Invitrogen™)

The mMESSAGE mMACHINE® T7 Ultra Kit combines a new cap analog —Anti-Reverse Cap Analog (ARCA)—with a patented high-yield transcription technology, to generate RNA transcripts that produce higher protein yields compared to other transcripts upon translation. The kit includes sufficient reagents for 50 reactions. Advantages of the mMESSAGE mMACHINE® T7 Ultra Kit:

• Synthesize more protein from in vitro-transcribed RNA
• Express RNA transcripts more efficiently both in vitro and in vivo
• Stabilize transcripts in vivo with included reagents for poly(A) tailing

ARCA-capped RNA is translationally more active
A base modification in ARCA results in its incorporation in the functional, translatable orientation only; traditional cap analog can be incorporated in both functional and nonfunctional orientations. As a result, incorporating ARCA into transcription reactions yields capped RNAs that are 100% translatable. This is further enhanced by the inclusion of poly(A) tails in mMESSAGE mMACHINE® T7 Ultra transcripts. Experiments comparing ARCA and ARCA/poly(A)–tailed transcripts to cap analog and cap analog/poly(A)–tailed transcripts indicate higher levels of protein synthesis with ARCA capped RNA .

What Is ARCA?
Anti-Reverse Cap Analog (ARCA) is a modified cap analog in which the 3' OH group (closer to m7G) is replaced with OCH3 (see schematic). Because of this substitution, the RNA polymerase can only initiate transcription with the remaining hydroxyl group, thus forcing ARCA incorporation in the forward orientation. As a result, 100% of the transcripts synthesized with ARCA at the 5' end are translatable, leading to a strong stimulatory effect on translation.

Proper capping of in vitro transcribed RNA
Proper capping of RNA promotes correct initiation of protein synthesis, as well as stability and processing of mRNA in vivo. Uncapped RNA is rapidly degraded by cellular RNases after microinjection or transfection into cells. Capped RNA is also typically translated more efficiently in in vitro translation systems, generating RNAs with cap analog incorporated only in the functional orientation. Therefore, substitution of traditional cap analog with ARCA results in the synthesis of capped RNAs that are 100% translatable.

MEGAscript™ SP6 Transcription Kit (Invitrogen™)

Novel transcription reaction conditions and Ambion's patented, high-yield technology allow the synthesis of 10–50 times the amount of RNA produced by conventional transcription reactions. Each Ambion® kit includes sufficient reagents for 40 reactions.

• Exclusive, ultrahigh yield technology is fast: 2 hour reaction time
• Amplifies aRNA for gene array analysis and other applications
• Efficiently incorporates many modified nucleotides

A typical 20 µl MEGAscript® reaction with 1 µg of the pTRI-Xef-1alpha control template will yield over 100 µg of transcript. The versatility of the MEGAscript® kit allows for manipulation of the reactions to include specialized reagents such as modified nucleotides, cap analog, or additional polymerase.

Accessory Products:
MessageAmp™ aRNA Amplification Kits are powered by MEGAscript® technology and have been developed especially for the amplification of cRNA prior to array analysis. To purify in vitro transcription products from free nucleotides, buffer components, and enzymes, Ambion recommends using the MEGAclear™ Kit (SKU#AM1908) and the MEGAclear™-96 Kit (SKU#AM1909).