RT primer mix?

Question

I received a RT reverse transcription kit from Qiagen.
It came with a primer mix (oligo dT + Random primers).
1. What happens in the RT reaction?
2. What would be my products?
3. Are the resulting cDNAs good for a number of gene specific RealTime PCRs?

Answer 1

During the RT reaction the reverse transcriptase synthesizes cDNA from mRNA using the oligo dT or random primers as a starting point. Your products will be cDNAs that represent all RNAs in your starting sample.

Yes, the resulting cDNAs will be good for many gene specific realtimes, but if your RNA is in very low amounts it may not get found. By far, the majority of your cDNA product will be for rRNA and tRNA unless you enriched your sample for mRNA.

Answer 2

I'd agree with everything the above person said except the part about rRNA and tRNA being the bulk of your cDNA. Since you're using oligo dT primers, chances are only mRNA will be selected.

Why?

mRNA is the only type of RNA that has a (3') poly A tail capable of binding to an oligo dT primer. Unless the rRNA or tRNA have a whole mass of adenine bases, chances are you'll get the mRNA.

Answer 3

1. You are basicly creating DNA from RNA.
2. DNA
3. No, because the cDNA is already spliced free of any introns and is just composed of exons.