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Reverse Transcriptases

M-MuLV Reverse Transcriptase

Note that EP0351 (small pack size) will be discontinued on March 31, 2012. We recommend an alternative product: RevertAid Reverse Transcriptase (not available in Canada). Please contact your local representative for a free sample. Full list of products to be discontinued.

- Thermal inactivation at 70°C in 10 min
- Recombinant enzyme
- LO certified
- Store at -20°C

Catalog#	Size, concentration	Supplied with:	Certificate of Analysis	MSDS
Catalog#	Size, concentration	5X Reaction Buffer	Certificate of Analysis	MSDS
EP0351	1000 u (20 u/µl) (for 25 reactions of 20 µl)	1.00 ml	EP0351
EP0352	5000 u (20 u/µl) (for 125 reactions of 20 µl)	5 x 1.00 ml	EP0352

Product information

Features

High yields of first strand cDNA up to 9 kb.
Optimum activity at 37°C.
Incorporates modified nucleotides (e.g., Cy3-, Cy5-, rhodamine-, aminoallyl-, fluorescein-labeled nucleotides).

Applications

First strand cDNA synthesis for RT-PCR and real-time RT-PCR.
Synthesis of cDNA for cloning and expression.
Generation of labeled cDNA probes for microarrays.
DNA labeling (3).
Analysis of RNA by primer extension (3).

Description

M-MuLV Reverse Transcriptase (RT) is an RNA- and DNA-dependent DNA polymerase. It can use either RNA or DNA to prime DNA synthesis. The enzyme possesses a ribonuclease H activity specific to RNA in RNA-DNA hybrids (1, 2).

Source

E.coli cells with a cloned fragment of the pol gene encoding Moloney Murine Leukemia Virus reverse transcriptase.

Molecular Weight

77.8 kDa monomer.

Definition of Activity Unit

One unit of the enzyme incorporates 1 nmol of dTMP into a polynucleotide fraction (adsorbed on DE-81) in 10 min at 37°C.

Enzyme activity is assayed in the following mixture: 50 mM Tris-HCl (pH 8.3), 4 mM MgCl₂, 10 mM DTT, 50 mM KCl, 0.5 mM dTTP, 0.4 MBq/ml [³H]-dTTP, 0.4 mM polyA·oligo(dT)_12-18.

Storage Buffer

The enzyme is supplied in:
50 mM Tris-HCl (pH 7.5), 0.1 M NaCl, 1 mM EDTA, 5 mM DTT, 0.1% (v/v) Triton X-100 and 50% (v/v) glycerol.

5X Reaction Buffer

250 mM Tris-HCl (pH 8.3 at 25°C), 250 mM KCl, 20 mM MgCl₂, 50 mM DTT.

Quality Control

The absence of endo-, exodeoxyribonucleases, phosphatases and ribonucleases confirmed by appropriate quality tests. Functionally tested in first strand cDNA synthesis.

Inhibition and Inactivation

Inhibitors: metal chelators, inorganic phosphate, pyrophosphate and polyamines (3).
Inactivated by heating at 70°C for 10 min.

Note

M-MuLV RT has significantly lower RNase H activity than Avian Myeloblastosis Virus (AMV) reverse transcriptase.

Patents, Licenses, Trademarks

Protocols & recommendations

RECOMMENDATIONS FOR USE

ADDITIONAL PROTOCOLS

Guidelines to Avoid RNase Contamination

RNA purity and integrity is essential for synthesis of full-length cDNA, which results in high quality RT-PCR products. Therefore, RNase contamination is always a concern when working with RNA. The RNA quality can be affected by RNase A, which is a highly stable contaminant of any laboratory environment. All components of the kit have been rigorously tested to ensure that they are RNase free. To prevent contamination both the laboratory environment and all prepared solutions must be free of RNases.

DEPC-treat all tubes and pipette tips to be used in the cDNA synthesis or use certified nuclease-free labware.
Use pipettes dedicated for RNA work.
Wear gloves when handling RNA and all reagents, as skin is an common source of RNases. Change gloves frequently.
Use certified reagents, including high quality water (e.g., nuclease-free or DEPC-treated Water).
Use an RNase inhibitor, such as RiboLock™ RNase Inhibitor, to protect template RNA.
Always assess the integrity of RNA prior to cDNA synthesis. For example, if sharp bands of both the human 18S rRNA (runs at approx. 1.9 kb) and the 28S rRNA (runs at approx. 5 kb) are formed during denaturing agarose gel electrophoresis of total RNA, the mRNA in the sample is considered to be intact.

First Strand cDNA Synthesis

Master Mix. To prepare several parallel reactions and to minimize the possibility of pipetting errors and contamination, prepare a RT master mix by adding all reaction components except RNA into one vial. Prepare enough master mix for the number of reactions and add one extra to compensate for pipetting errors. Sample template RNA into individual tubes and keep on ice. Aliquote the prepared master mix into tubes with RNA. Mix and briefly centrifuge all components after thawing, keep on ice.

Add into sterile, nuclease-free tube on ice in the order given:

Total volume		11.5 µl
Template RNA	Total RNA or Poly(A) RNA or Specific RNA	100 ng – 5 µg 10 ng – 0.5 µg 0.01 pg – 0.5 µg
Primer	Oligo(dT)₁₈ primer (#SO131) or Random hexamer primer (#SO142) or Gene-specific	0.5 µg (100 pmol) 0.2 µg (100 pmol) 15-20 pmol
Water, nuclease free (#R0581)		to 11.5 µl

Optional: If RNA template is GC-rich or is known to contain secondary structures, mix gently, centrifuge briefly and incubate at 65°C for 5 min, chill on ice, briefly centrifuge and place on ice.

Add into the same tube in the indicated order:

Total volume	20 µl
5X Reaction Buffer	4 µl
RiboLock™ RNase Inhibitor(#EO0381)	0.5 µl (20 u)
dNTP Mix, 10 mM each (#R0191)	2 µl (1 mM final concentration)
M-MuLV Reverse Transcriptase	2 µl (40 u)

Mix gently and briefly centrifuge.
If oligo(dT)₁₈ primer or gene-specific primer is used, incubate 60 min at 37°C.
If random hexamer primer is used, incubate 10 min at 25°C followed by 60 min at 37°C.
Terminate the reaction by heating at 70°C for 10 min.

Do not heat inactivate enzyme prior to analysis of long cDNA to avoid cleavage.

The reverse transcription reaction product can be directly used in PCR, qPCR or second strand cDNA synthesis or stored at -20°C for up to one week. For longer storage -70°C is recommended. Avoid freezing/thawing of cDNA.
Use 2 µl of the reaction mix to perform PCR in 50 µl reaction volume.

Synthesis of cDNA Probes with High Specific Radioactivity and Non-radioactively Labeled cDNA

I. Synthesis of cDNA probes with high specific radioactivity

Mix and briefly centrifuge all components after thawing, keep on ice.

Add into sterile, nuclease-free tube on ice in the order given:

Total volume		7.5 µl
Template RNA	Total RNA or	100 ng - 5 µg
	Poly(A) RNA or	10 ng - 0.5 µg
	Specific RNA	0.01 pg - 0.5 µg
Primers	Oligo(dT)₁₈ (#SO131) or	0.5 µg (100 pmol)
	Random Hexamer (#SO142) or	0.2 µg (100 pmol)
	Gene-specific	15-20 pmol
Water nuclease free (#R0581)		to 7.5 µl

Optional: if RNA template is GC-rich or is known to contain secondary structures, mix gently, centrifuge briefly and incubate at 65°C for 5 min, chill on ice, briefly centrifuge and place on ice.

Add into the same tube in the indicated order:

Total volume	20 µl
5X reaction buffer	4 µl
RiboLock™ RNase Inhibitor (#EO0381)	0.5 µl (20 u)
dGTP, dCTP, dTTP mix, 10 mM each	1 µl
0.1 mM dATP	4 µl
[alpha-³²P]-dATP, 3000 Ci/mmol	1 µl
M-MuLV Reverse Transcriptase	2 µl (40 u)

Mix gently and centrifuge to collect all drops.
If Oligo(dT)₁₈ primer or gene-specific primer is used, incubate 60 min at 37°C. If random hexamer primer is used, incubate 10 min at 25°C followed by 60 min at 37°C.
Stop the reaction by adding 5 µl of 0.5 M EDTA, pH 8.0 (#R1021).
Optional. Hydrolyze RNA by the addition of equal volume (25 µl) of 0.6 M NaOH and incubation at 70°C for 30 min.
Remove unincorporated dNTPs by spin column (e.g. GeneJET PCR purification Kit, #K0701) or chromatography on a Sephadex® G-50 column.
Expect specific radioactivity of >10⁷ dpm/µg.

Note

To achieve higher specific activities (over 10⁸ dpm/µg), use up to 100 µCi of [alpha-³²P]-dATP in the labeling mixture. To keep the total reaction volume of 20 µl, vacuum-evaporate 10 µl of [alpha-³²P]-dATP (10 mCi/ml) to 1 µl in a separate tube.

II. Synthesis of non-radioactively labeled cDNA

The protocol above can be used for synthesis of non-radioactive labeled cDNA using biotin-11-dUTP, fluorescein-12-dUTP, DIG-dUTP or aminoallyl-dUTP:

normal dTTP is subsituted with labeled-dUTP at a molar ratio of 1:3 - 1:4,
reaction time is prolonged to 2-6 hours.

Removal of Genomic DNA from RNA Preparations

Add to an RNase-free tube:

RNA 1 µg

10X reaction buffer with MgCl₂ 1 µl

DNase I, RNase-free 1 µl (1 u)

DEPC-treated Water to 10 µl

Total volume 10 µl
Incubate 30 min at 37°C.
Add 1 µl of 50 mM EDTA and incubate 10 min at 65°C. RNA hydrolyzes if heated in the absence of a chelating agent (1).
Use the prepared RNA as a template for reverse transcriptase.

Note

Do not use more than 1 u of DNase I, RNase-free per µg of RNA.
Reaction mixture can be scaled up for larger amounts of RNA. The recommended final concentration of RNA is 0.1-0.2 µg/µl.
RiboLock™ RNase Inhibitor (#EO0381), typically at 1 u/µl, can also be included in the reaction mixture to inactivate type A RNases potentially present in the initial RNA solution

Reference

Wiame, I., et al., Irreversible heat inactivation of DNase I without RNA degradation, BioTechniques, 29, 252-256, 2000.

References

Verma, I.M., Reverse transcriptase, The Enzymes (Boyer, P.D., ed), Academic Press Inc., vol. 14, 87-103, 1981.
Gerard, G.F., D’Alessio, J.M., Methods in Molecular Biology, 16, Humana Press, Totowa, N.J., 73-93, 1993.
Sambrook, J., Russell, D.W., Molecular Cloning: A Laboratory Manual, the third edition, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, New York, 2001.

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