IMPLICATIONS FOR THE LIGASE CHAIN-REACTION IN GASTROENTEROLOGY

The ligase chain reaction (LCR) is a new DNA detection method that use s thermostable ligase to discriminate exquisitely and amplify single b ase changes in genes of medical interest. This enzyme specifically lin ks two adjacent oligonucleotides when hybridized to a complementary ta rget only when the nucleotides are perfectly base-paired at the juncti on. Oligonucleotide products are exponentially amplified by thermal cy cling of the ligation reaction in the presence of a second set of adja cent oligonucleotides, complementary to the first set and the target. A single-base mismatch prevents ligation and amplification, thus disti nguishing a single base mutation from the normal allele. The use of a thermostable ligase allows the enzyme to survive thermal cycling in a fashion analogous to Taq polymerase in the polymerase chain reaction. The assay is compatible with nonradioactive detection and has the pote ntial for automation. Although still in its early stages of developmen t, LCR is expected to find many uses in the field of gastroenterology and in medicine in general. In this review we briefly describe how LCR works and discuss potential areas of application in gastroenterology.