title: Real-time genotyping with oligonucleotide probes containing locked nucleic acids.
abstract: Oligonucleotide probes containing locked nucleic acid (LNA) hybridize to complementary single-stranded target DNA sequences with an increased affinity compared to oligonucleotide DNA probes. As a consequence of the incorporation of LNA residues into the oligonucleotide sequence, the melting temperature of the oligonucleotide increases considerably, thus allowing the successful use of shorter LNA probes as allele-specific tools in genotyping assays. In this article, we report the use of probes containing LNA residues for the development of qualitative fluorescent multiplex assays for the detection of single nucleotide polymorphisms (SNPs) in real-time polymerase chain reaction using the 5'-nuclease detection assay. We developed two applications that show the improved specificity of LNA probes in assays for allelic discrimination. The first application is a four-color 5'-nuclease assay for the detection of SNPs for two of the most common genetic factors involved in thrombotic risk, factor V Leiden and prothrombin G20210A. The second application is a two-color assay for the specific detection of the A-to-T tranversion in codon 6 of the beta-globin gene, responsible for sickle cell anemia. Both real-time genotyping assays were evaluated by comparing the performance of our method to that of a reference method and in both cases, we found a 100% concordance. This approach will be useful for research and molecular diagnostic laboratories in situations in which the specificity provided by oligonucleotide DNA probes is insufficient to discriminate between two DNA sequences that differ by only one nucleotide.
authors.affiliation: Bio-Rad Laboratories, 2000 A. Nobel Drive, Hercules, CA 94547, USA. luis_ugozzoli@bio-rad.com
authors.forename: Luis A
authors.initials: LA
authors.lastname: Ugozzoli
authors.forename: David
authors.initials: D
authors.lastname: Latorra
authors.forename: Randi
authors.initials: R
authors.lastname: Puckett
authors.forename: Randi
authors.initials: R
authors.lastname: Pucket
authors.forename: Khalil
authors.initials: K
authors.lastname: Arar
authors.forename: Keith
authors.initials: K
authors.lastname: Hamby
mesh_terms: D000483:Alleles; D000755:Anemia, Sickle Cell / Q000150:complications / Q000235:genetics; D001483:Base Sequence; D003124:Colorimetry; D003851:Deoxyribonucleases / Q000737:chemistry / Q000378:metabolism; D005165:Factor V / Q000235:genetics; D005821:Genetic Techniques; D005838:Genotype; D005914:Globins / Q000235:genetics; D006801:Humans; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D009696:Nucleic Acids / Q000235:genetics*; D015345:Oligonucleotide Probes / Q000737:chemistry / Q000235:genetics*; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide; D011516:Prothrombin / Q000235:genetics; D013927:Thrombosis / Q000235:genetics
chemical_list: D009696:Nucleic Acids; D015345:Oligonucleotide Probes; C095381:factor V Leiden; D005165:Factor V; D011516:Prothrombin; D005914:Globins; D003851:Deoxyribonucleases