93 results about "Repeated sequence" patented technology

The invention relates to a surface-enhanced Raman technology based on signal-off and used for detecting intracellular telomerase activity. According to the technology, graphene, carbon nitride, MoS2, SiO2 and the like are taken as carriers, nano-gole or nano-silver with controllable dimension and morphology or a composite magnetic nano-particle with a core-shell structure is supported by the carriers, and then a hairpin probe containing a telomerase primer and a Raman molecule beacon is fixedly disposed on the nano=particle surface, so that the high-sensitivity high-selectivity SERS detection method based on signal-off is established. When a target exists, the primer extends and generates a DNA chain with a repeat sequence under the effect of telomerase, and the DNA chain is hybridized with the probe molecule, then the DNA hairpin structure is opened, a Raman signal molecule with the single-chain labeled end is far away from a Raman substrate, the Raman signal is reduced, and high-sensitivity detection on telomerase is realized. The probe prepared by taking Hela cervical carcinoma cell as a model realizes intracellular telomerase activity detection and dynamic detection on intracellular telomerase activity variation under effect of a telomerase inhibiting medicament. By using multiple cells for imaging, the probe is confirmed to be capable of distinguishing tumor cells and normal cells.

The way to design a “filled” site (which contains an interspersed element) primer set to target a particular locus is to design one of the two primers such that it encompasses that unique information (e.g., interspersed element+flanking genomic sequence+direct repeat). The way to design an “empty” site primer is to design one of the two primers such that the entire direct repeat sequence in addition to flanking genomic sequence is included on both sides. To improve efficiency, the “empty” site primer designed around the direct repeat should not be too long. This primer design of the present invention allows for the ability to test any type of interspersed genetic element containing characteristic direct repeat sequences (direct repeats). This gives the option of many new polymorphic marker sites because Alu elements are not the only interspersed genetic elements having direct repeats flanking their core sequence.

The invention relates to a dual temperature rapid cycling fluorescence quota PCR method for detecting telomerase activity and a kit. The method provided by the invention comprises steps of: combining primers, which are the anchored hairpin primers (AHP), with a duplex scorpion primers (DS) to form a DS / AHP-TRAP system; detecting the activity of telomerase in immortalized cell protein extracts under the condition of dual temperature rapid cycling PCR; taking a telomerase extension product R6 containing 6 telomere repeat sequences as a quantitative standard substance, and drafting a quantitative curve of the extension product of the detected telomerase; comparing the quantitative standard curve of the immortalized cell sample and that of R6 to obtain an anastomosis graph of the detected telomerase activity quantitative curve and the telomerase extension product quantitative curve; supposing that a TPG value is a telomerase extension product generated by an immortalized cell and determining the number of R6 represented by the TPG value. The kit provided by the invention can be used to accomplish a real-time detection of telomerase activity in large quantities on the fluorescence quota PCR instrument in a simpler and faster manner, and has a wide prospect in the early diagnosis of malignant tumor and the screening of anticancer drugs.

Nucleic acid (e.g., DNA) hybridization probes are described which comprise a labeled, single copy nucleic acid which hybridizes to a deduced single copy sequence interval in target nucleic acid of known sequence. The probes, which are essentially free of repetitive sequences, can be used in hybridization analyses without adding repetitive sequence-blocking nucleic acids. This allows rapid and accurate detection of chromosomal abnormalities. The probes are preferably designed by first determining the sequence of at least one single copy interval in a target nucleic acid sequence, and developing corresponding hybridization probes which hybridize to at least a part of the deduced single copy sequence. In practice, the sequences of the target and of known genomic repetitive sequence representatives are compared in order to deduce locations of the single copy sequence intervals. The single copy probes can be developed by any variety of methods, such as PCR amplification, restriction or exonuclease digestion of purified genomic fragments, or direct synthesis of DNA sequences. This is followed by labeling of the probes and hybridization to a target sequence.

The invention provides a plant site-directed recombination method mediated by repeated fragments. Specifically, the present invention provides a donor DNA with a specific repeat sequence, and a reagent combination for gene editing. According to the invention, the donor DNA with a specific structure is adopted, and a specific site of a target gene is cut by means of a site-directed cutting nuclease, so that the donor DNA fragment is efficiently integrated into a cutting site.

A method for amplifying oligonucleotide in vitro by polymerase-endonuclease chain reaction (PECR) which utilizes a single-stranded DNA probe containing repeat sequences, extends a target oligonucleotide by a thermostable DNA polymerase, cleaves extended products with a thermostable endonuclease, and amplifies target oligonucleotide by thermocycling. In PECR, a specific oligonucleotide is exponentially amplified using one single probe instead of a pair of primers, and the reaction is precisely controlled by thermal cycles whose parameters are flexibly adjustable according to length, sequence, melting temperature and initial amount of the target oligonucleotide. Amplification speed depends totally on initial amount of target oligonucleotide present in the reaction system. The method can be used to amplify specific small nucleic acids, such as oligonucleotides and microRNAs, and further conduct quantitative analysis. PECR is easy to conduct with high efficiency, specificity and stability, and thus can be widely used in molecular biology studies.

The way to design a “filled” site (which contains an interspersed element) primer set to target a particular locus is to design one of the two primers such that it encompasses that unique information (e.g., interspersed element+flanking genomic sequence+direct repeat). The way to design an “empty” site primer is to design one of the two primers such that the entire direct repeat sequence in addition to flanking genomic sequence is included on both sides. To improve efficiency, the “empty” site primer designed around the direct repeat should not be too long. This primer design of the present invention allows for the ability to test any type of interspersed genetic element containing characteristic direct repeat sequences (direct repeats). This gives the option of many new polymorphic marker sites because Alu elements are not the only interspersed genetic elements having direct repeats flanking their core sequence.

The invention provides a microsatellite site for detecting MSI, its screening method and application. The screening method includes: selecting microsatellite loci with A or T single-base repeat sequences of ≤15 bp and whose flanking sequence similarity value is lower than the similarity threshold, and recording them as the first locus set; obtaining sequencing data of multiple MSS samples and Screen and count the type of repeating unit and the frequency of each repeating unit in the first locus set; select the locus that satisfies the second condition as the second locus set, and the second condition includes: 1) the highest frequency The type of repeating unit is consistent with the reference sequence; 2) The capture efficiency in the process of library construction and sequencing is higher than the capture threshold; 3) The polymorphism in the population is less than 5%; count and retain every Sites where there is a significant difference in the deletion ratio between the negative sample group and the positive sample group. The screened sites can improve the sensitivity and specificity of detection.