cDNA Synthesis Protocols

3'-End cDNA Amplification Using Classic RACE Protocol To generate "3'-end" partial cDNA clones, mRNA is reverse-transcribed using a "hybrid" primer (Qtotal, QT) that consists of two mixed bases (GATC/GAC followed by [T]17) and a unique 35-base oligonucleotide sequence (QI-QO).  Amplification is then performed using a primer containing part of this sequence (Qouter, Qo) (which now binds to each cDNA at its 3'-end) and a primer derived from the gene of interest, GSP1 (gene-specific primer 1).

5'-End cDNA Amplification Using Classic RACE Protocol To generate "5'-end" partial cDNA clones using classic RACE, the first-strand products are generated by reverse transcription (primer extension) from a known gene-specific primer (GSP-RT).  Then, a poly(A) tail is appended using terminal deoxynucleotidyltransferase (Tdt) and dATP.  Amplification is carried out using three primers.

5'-End cDNA Amplification Using New RACE Protocol New RACE, a variation of RNA ligase-mediated-RACE (RLM-RACE) (Liu and Gorovsky 1993) departs from classic RACE (see 5'-End cDNA Amplification Using Classic RACE) in that an "anchor" primer is attached to the 5'-end of the mRNA before the reverse transcription step; hence the anchor sequence becomes incorporated into the first-strand cDNA if, and only if, the reverse transcription proceeds through the entire length of the mRNA of interest.

Amplification of cDNA Generated by Reverse Transcription of mRNA Protocol An oligodeoxynucleotide primer hybridized to mRNA is extended by an RNA-dependent DNA polymerase to create a cDNA copy that can be amplified by PCR.  Depending on the purpose of the experiment, the primer for first-strand cDNA synthesis can be specifically designed to hybridize to a particular target gene, or a general primer such as oligo(dT) can be used to prime cDNA synthesis from essentially all mammalian mRNAs

Cap-Switching RACE Protocol This method, for the selective amplification of full-length cDNA ends, involves the addition of an adapter during reverse transcription.  This method takes advantage of the propensity of Moloney murine leukemia virus reverse transcriptase (MMLV RT) to append two to four cytosines to the 3'-end of newly synthesized cDNA strands.  The additional residues are added when the enzyme reaches the 5'-cap structure at the end of the mRNA template.

First strand cDNA synthesis with Ready-To-Go Beads Protocol This cDNA synthesis system simplifies your work dramatically.  All reaction components are premixed and lyophylised.  You have to add your RNA and (for Your-Prime beads) the primer.  Another advantage of the system is a little number of pipetting steps required, and therefore reduced risk of Rnase contamination and RNA degradation.

First strand cDNA synthesis with Super Script II Protocol This method of first strand cDNA synthesis is more efficient than Ready-to-Go beads.  You can use as little as 100ng total RNA and still detect you gene expression in PCR.

Mixed Oligonucleotide-primed Amplification of cDNA MOPAC Protocol In MOPAC, the amino-terminal and carboxy-terminal sequences of a peptide are used to design two redundant families of oligonucleotides encoding the aminoand carboxy-terminal sequences of the peptide.  The primers are used either to amplify a segment of cDNA prepared by RT-PCR from a tissue known to express the protein or to amplify a segment of DNA from an established genomic or cDNA library.

Rapid Amplification of 3' cDNA Ends 3'-RACE Protocol 3'-RACE reactions are used to isolate unknown 3' sequences or to map the 3' termini of mRNAs onto a gene sequence.  3'-RACE requires knowledge of a small region of sequence within either the target RNA or a partial clone of cDNA.  A population of mRNAs is transcribed into cDNA with an adaptor-primer consisting at its 3' end of a poly(T) tract and at its 5' end of an arbitrary sequence of 30-40 nucleotides.

Rapid Amplification of 5' cDNA Ends 5'-RACE Protocol This method is used to extend partial cDNA clones by amplifying the 5' sequences of the corresponding mRNAs.  The technique requires knowledge of a small region of sequence within the partial cDNA clone.  During PCR, the thermostable DNA polymerase is directed to the appropriate target RNA by a single primer derived from the region of known sequence.

Synthesis of Radiolabeled, Subtracted cDNA Probes Using Oligo(dT) as a Primer Protocol Protocol describes the preparation of subtracted cDNA probes by hybridization to an mRNA driver, followed by purification of the single-stranded radiolabeled cDNA by hydroxyapatite chromatography.  Before preparing the probe, it is a good idea to have filters (which contain the cDNA library to be screened) ready to hybridize.