Abstract:
The present disclosure relates to methods of detecting nucleic acid hybridization by monitoring an output signal. Some advantageous embodiments include techniques which can augment the signal. One such technique involves catalytic detection, such as with a peroxidase or other enzyme. Another technique involves "on-chip" amplification to enlarge the nucleic acid after hybridization has occurred.
Abstract:
Disclosed herein are methods of destabilizing double-stranded nucleic acid hybridization using an enzyme comprising DNA N-glycosylase activity. Also disclosed herein is the detection of a double-stranded target DNA wherein the hybridization of duplex strands has been at least partially disrupted thereby permitting invasion of a probe strand. Also disclosed herein are methods of using an enzyme comprising DNA N-glycosylase activity to generate single-stranded circular nucleic acids.
Abstract:
The present application provides methods and compositions for use in detecting the presence of a target nucleic acid in a sample. In some embodiments, the methods employ sequestering agents which specifically interact with complementary nucleic acids which will be ligated together if the target nucleic acid is present in the sample. Detection of a ligation product comprising the complementary nucleic acids indicates that the target nucleic acid is present in the sample.
Abstract:
The present disclosure provides methods and compositions for conducting an assay to detect nucleic acid hybridization in the presence of oxygen. In particular, ruthenium complexes having a reduction potential that does not coincide with the reduction potential of molecular oxygen are disclosed and amperometric techniques for their use are described. In preferred embodiments, the ruthenium complex is ruthenium (III) pentaamine pyridine and the nucleic acid hybridization event that is detected is DNA hybridization. Further, techniques for enhancing detectable contrast between hybridized and unhybridized nucleic acids are disclosed. In particular, the use of elongated target strands as well as the use of uncharged probe strands are discussed.
Abstract:
The present invention relates to the detection of somatic cell mutations, particularly as part of a method to screen for cancer or precancer. The disclosure includes techniques for extracting and isolating oligonucleotides from a patient and conducting hybridization assays. Preferred embodiments include a combination of the following steps: extracting a biological sample from a patient, purifying a nucleic acid from a biological sample, amplifying a nucleic acid, isolating a nucleic acid in single stranded form, cyclizing a nucleic acid, elongating a nucleic acid, controlling hybridization stringency, amplifying a nucleic acid on a chip, and detecting hybridization.
Abstract:
A universal tag assay is disclosed wherein at least one invasive cleavage reaction (ICR) is used to generate tagged molecules having identifier tags corresponding to target nucleotide sequences, and further wherein hybridization of any tagged molecule with a complementary detection probe on a universal detector indicates the presence of the corresponding target in the sample being assayed. Preferred embodiments include the use of ICR to generate molecules suitable for use in the universal tag assay to detect variant nucleotide sequences including single nucleotide polymorphisms (SNPs), allelic variants, and splice variants. Hybridization of tagged molecules to detection probes is preferably detected by electrochemical readout, in particular the use of ruthenium amperometry to detect hybridization of identifier tags to detection probes immobilized on a universal detector, preferably a universal chip having gold or carbon electrodes.
Abstract:
The present disclosure relates to methods for generating single-stranded DNA molecules of defined sequence and length. Specifically, a region of template containing target sequence is amplified by PCR or RCA, exogenous sequence is introduced by primers or probes used in amplification, double-stranded amplification products are converted to single-stranded amplification products, and single-stranded amplification products are trimmed to produce short single-stranded DNA molecules of defined sequence and length.
Abstract:
The present invention disclosure provides methods and compositions for a universal tag assay wherein a universal detector having detection probes is incubated with tagged molecules having identifier tags corresponding to targets, and hybridization of an identifier tag to a complementary detection probe indicates the presence of the corresponding target in the material being assayed. In particular, the invention disclosure provides methods and compositions for detecting target nucleotide sequences in a sample by target-dependent manipulations that generate tagged molecules having identifier tags corresponding to target nucleotide sequence, where incubation of tagged molecules with a universal detector having detection probes permits hybridization of identifier tags to complementary detection probes, thereby indicating the presence of the target nucleotide sequence corresponding to each identifier tag. Preferred embodiments include use of the universal tag assay for detecting variant sequences including single nucleotide polymorphisms (SNPs), allelic variants, and splice variants. Preferred embodiments further include the use of ruthenium amperometry to detect hybridization of tagged DNA or RNA molecules to detection probes immobilized on a universal detector, preferably a universal chip having gold or carbon electrodes.
Abstract:
The present disclosure relates to methods for generating single-stranded DNA molecules of defined sequence and length using ligase chain reaction (LCR). Specifically, a region of template containing target sequence is amplified by LCR, exogenous sequence is introduced by LCR primers or probes used in amplification, and LCR products may be used in further amplification steps involving rolling circle amplification (RCA) or polymerase chain reaction (PCR). LCR products may include sequence complementary to the backbone of a padlock probe, where the LCR product hybridizes to a padlock probe and after ligation of the padlock, serves as polymerazation primer. After amplification, single-stranded amplification products are trimmed to produce short single-stranded DNA molecules of defined sequence and length.