On Oct. 20, the Federal Register carried an announcement from theNational Institutes of Health Office of Technology Transfer (OTT)inviting biotechnology firms to collaborate with the NationalCancer Institute in commercializing an invention that throws lighton assaying polymerase chain reaction (PCR) products.The proposed technique visualizes amplified DNA by means of ahighly fluorescent guanosine analog, pteridine. As described in apatent application (No. 08/245,923., filed May 18 by NCI), "thecompound, when site-specifically incorporated into anoligonucleotide, by an automated DNA synthesizer, is accepted bythe endonuclease HIV-1 integrase in place of guanosine in thesequence-specific cleavage site of a short double strand of DNA."The description hypothesizes that the polymerase may take upsufficient pteridine triphosphate to detect a PCR product by itsfluorescence.The first inventor of this light-emitting, patent-pending PCR probe is enzyme chemist Mary Hawkins of NCI'spediatrics branch. Just what does pediatrics _ and for that matter,HIV or cancer_ have to do with developing a rapid, real-time wayof determining the outcome, positive or negative, of an all-purposePCR reaction?Hawkins explains: "Initially, I had developed the assay for dideoxyinosine in AIDS therapy, which the FDA used in approving thatdrug. Most of our data were based on testing children, because Iwork in the pediatric branch of NCI."The AIDS connection, she told BioWorld Today, "relates to theHIV restriction enzyme, integrase. This takes the viral genomicDNA from the reverse transcription and inserts it into the humanhost cell's DNA. It was while we were developing an assay forintegrase that the broader PCR application emerged."Hawkins added, "This invention has nothing to do with AIDS. Itapplies to any PCR analysis. If you're looking at a certain gene thatyou know is carried by a disease, like HIV or anything PCR is usedfor, you could employ our visualization system _ if it provesworkable."Finding that proof is one reason Hawkins is looking for anindustrial partner. "We need to have someone doing the PCRaspects," she said. "including development of a kit for its use. Thebiggest thing we need is support, in people as well as funding. Andat some point, we're going to need large-scale quantities of thiscompound, pteridine triphosphate, once we succeed in making itchemically. That undertaking," she added, "is proving horrendous.Another way of approaching the problem is to make thetriphosphate enzymatically. Our commercial CRADA partnerwould be joining us in a totally original area."This pterin is a guanine analog that is fluorescent. (Guanine is oneof the four nucleotide bases in DNA or RNA.) Pterin is a two-ringcompound originally discovered in the pigment of butterfly wings.Aptly, Hawkins observed, "If this project flies, it will be verymarketable as a kit for PCR applications."Editor's Note: For CRADA information, (deadline, 5 p.m., Nov.30), consult Eric Hale, NCI Office of Technology Development,(301) 496-0477; for patent licensing, Robert Benson, NIH Office ofTechnology Transfer, (301) 496-7056, ext. 267; for technicalquestions concerning this invention, Mary Hawkins, (301) 496-1756. n
-- David N. Leff Science Editor
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