Advances in PCR: Roche Innovations
Since the late 1980s, Roche has committed to and invested in developing and improving polymerase chain reaction (PCR) technology. After acquiring rights to PCR in 1991, Roche scientists have continued to improve the PCR process, making it a standard tool across all biological sciences.
Reverse Transcription PCR: RT-PCR
In 1991, the same year that Roche acquired the rights to PCR, Reverse transcription PCR (RT-PCR) is developed using a single enzyme that withstands heat and can make a DNA strand from RNA, facilitating diagnostic tests for RNA viruses. This is helpful in identifying, studying and better understanding retroviruses, infections like HIV, that have RNA instead of DNA in their genomes.
The RT-PCR is completed in two steps: the RT reaction followed by PCR amplification.
Step 1: Using a reverse transcriptase in a tube with the RNA sample, RNA is reverse transcribed into a “complementary” DNA (cDNA) strand. This matches the RNA nucleotides with their corresponding DNA nucleotides, creating a DNA sequence.
Step 2: Using the cDNA, the three step PCR process copies the DNA during multiple cycles of DNA amplification. From there, the DNA may be used in diagnostics and monitoring tests.
In 2003, Roche released the COBAS® TaqMan® Analyzer that supported three COBAS® TaqMan® IVD tests; human immunodeficiency virus-1 (HIV-1), hepatitis B virus (HBV) and hepatitis C virus (HCV) in Europe. These were the first PCR tests that allow for amplification and detection and occur at the same time. The process was termed Real-Time PCR.
Using fluorescent probes, the DNA produced in the PCR amplification reaction may be monitored in real time to detect the presence of the viral pathogen. As the amplified pathogen DNA accumulates at every PCR cycle, the amplified DNA segments “light up”, allowing a quantitative detection of the virus. Because PCR and detection could now be completed simultaneously, not sequentially, the time to result is decreased and human interaction with the samples is decreased, lowering the risk of contamination.
In 2007, Roche released the COBAS® AmpliPrep/COBAS® TaqMan®, the first fully automated Real-Time PCR system. The system, comprised of two instruments, one that completes sample preparation, the other performs the PCR process and detection of the pathogen DNA in real time. This advance further reduces the time needed for detection and diagnosis and reduces the risk of contamination of the sample being tested.
With an ongoing commitment to quality and innovation, Roche will continue to invest, research and improve on PCR technology.