Friday, August 28, 2009

Lab Technique - RT-PCR

RT-PCR stands for real-time polymerase chain reaction. Both PCR and RT-PCR are able to amplify target DNA sequences but the value-addedness of RT-PCR comes from the fact that it can also detect the amplified sequence in real-time. For PCR, agarose gels are required for the detection of the amplified sequence and it can only done after the amplification process. This becomes very time consuming. Because of the increased number of manual steps involved in the detection of PCR products, it is likely that the rate of error due to contamination or other human error is higher than RT-PCR.



(Image taken from http://bio-rad.gene-quantification.info/)

This is a real-time PCR system (CFX96™ Real-Time PCR Detection System from Bio-Rad) that my lab uses. It is able to perform several assays at any one time and is relatively user-friendly.

The procedures to run RT-PCR are easy as the vendor would have provided you with sufficient information to run your samples. For example, for the TaqMan probes that I was using, I was required to add in 10µL of TaqMan Universal PCR Master Mix, 1µL of Assay Mix, desired amount of sample and RNase-free water. The parameters for RT-PCR (not mentioned) and formula are all provided by the vendor. As long as the protocol is followed, every thing should be a-ok.

Lastly, RT-PCR can be used for quantification of gene expression, detection of pathogens and genotyping. There are of course, more applications out there than that that I've listed. It is really how creative anyone can get to exploit this useful machine.

Yvonee Chew 0703189A

P/S Where is Jacelyn?

5 comments:

  1. hi yvonne,

    since there is much more advantages in using RT-PCR, does your lab still use PCR? Or only under certain conditions?

    zi shuang :)

    ReplyDelete
  2. Hello Zi Shuang,

    Currently, we're using RT-PCR because the project requires the use of RT-PCR =)

    Yvonee
    0703189A

    ReplyDelete
  3. Hello!
    so what exactly is about detecting the amplified sequence in REAL-TIME? can you elaborate more about it?=) Also, for PCR, gel electropheresis is used to interpret the PCR products, but for RT-PCR how do you interpret the results?

    Happy SIPing!
    Yong Herng
    0702243G

    ReplyDelete
  4. hi y-vonee (HAHA)

    i'm using RT-PCR too! and it's bio-rad too! but different models! haha. and the procedure is tedious!

    are there other ways to confirm PCR results other than performing gel electrophoresis?

    lim jia hui
    tgo1 0703605f group 2

    ReplyDelete
  5. Yong Herng:
    To put it simply, it is just amplifying and detecting the amplified sequence simultaneously as we run RT-PCR. The machine will detect the fluorescence (increased products = increased fluorescence)and plot the graph comparing the cycle numbers and relative fluorescence units.

    Alternatively, a melt-curve can also be obtained to see the melting point of the products. If there is no contamination, mispriming etc, the melting point for the products should be the same. Hence this replaces the need for gel electrophoresis

    Joey:
    You know, I'm always worried that I will mix up or anything bad! Especially when my co-mentor always ask if he can trust my pipetting skills lol!

    Anyway, I'm not sure about other ways but from what I know, yes, gel electrophoresis is the only way.

    Yvonee
    0703189A

    ReplyDelete