Research Services:
Genetic Stability Testing Advances with Quantitative PCR
Originally Published in CanBiotech BioMed Outsourcing Newsletter: Volume 1, Issue 1, September 2002

By Lark Technologies Inc.
Jaime Nicole Thomas
Services Include: Custom DNA Sequencing, Real-Time Quantitative PCR Services, Other Molecular Biology Services,Genetic Stability Testing, Genetically Modified Organism Testing, Genotyping

Today we use recombinant gene expression systems, from bacterial to mammalian, to produce many types of important products.  In order to produce reliable and stable products, the cell banks themselves must undergo rigorous testing and quality assurance.  To obtain regulatory approval, the producer must show that the culture is pure, the cells are stable, and the DNA gene expression system is intact. 

During the production of cell lines, the scientific investigator may choose to run a variety of tests in order to ensure genetic stability.  Copy number of the plasmid or insertion number is usually needed for both mammalian and bacterial cell banks, as is determining the sequence of relevant RNA transcripts and DNA.  Investigators with mammalian cell banks are also interested in confirming the structure of the insert by Southern blot.  Bacterial banks need to be screened for contaminating phage and plasmid loss.  Many final products need to be screened for contaminating host DNA.

Recent technological advances have streamlined many of these investigations.  Traditionally, scientists have used Southern blot as a method to determine the plasmid or insertion copy number.  Quantitative PCR (QPCR) offers a faster and more cost-effective alternative to Southern blot copy number analysis, both in bacterial and mammalian systems.   This method allows for gene-specific amplification using a dual-labeled fluorescent probe and real-time detection.  Lark Technologies has perfected QPCR copy number analysis over the past four years and includes a statistical analysis with standard deviations and confidence intervals in the final report.

Lark also uses the latest advances in automated sequencing, including the newest capillary sequencing instruments, to provide clients fast and accurate information.  Lark has provided sequencing services for FDA submission since inception and has vast experience at isolating DNA and RNA from cell banks.  Lark can provide sequence for cell bank plasmids and inserted genes, as well as for RNA transcripts (via reverse transcription followed by PCR).

Lark Technologies, Inc. is the leading international molecular biology contract research
organization (CRO).  Since its launch in 1989, Lark has developed an extensive portfolio of genomics-based services to support the growing needs of its commercially driven client base.  Lark has served over 3,000 customers, including most of the large pharmaceutical companies, and has established long-term relationships with these clients.