摘要:
In accordance with the present invention, methods are presented for labeling a cDNA strand with a labeled ribonucleotide base precursor which upon exposure to Mg2+, heat and base cleaves the cDNA at each place of incorporation of an RNA. In accordance with an aspect of the present invention, compounds selected from the group consisting of are incorporated into the growing strand of a cDNA by a reverse transcriptase or a mutant reverse transcriptase. After subject the strands to Mg2+, base and heat, the 3′ OH causes cleavage of the cDNA leaving a 2′OH phosphate with a biotin label. The biotin provides a label which may be bound to streptavidin and thereafter hybridized to a nucleic acid array.
摘要:
In one aspect of the invention, methods and compositions are provided for fragmenting nucleic acid samples. Fragmented nucleic acid samples may be used for hybridization with microarrays.
摘要:
Methods are provided for detecting hybridization of a polynucleotide to a nucleic acid array by chemically modifying the polynucleotide to contain a detectable label. According to one aspect of the present invention, a method is provided for detecting the presence of a mRNA in a nucleic acid sample, the method having the steps of providing a mRNA sample and azido modified nucleotides, hybridizing a primer to the mRNA, reversed transcribing the mRNA to provide azido modified DNA, followed by reacting the azido groups with a detectable label, hybridizing the labeled RNA to a nucleic acid array and detecting the presence of the mRNA. Still other methods are provided for detecting the presence or absence of a polynucleotide of interest on a nucleic acid array, the method having the steps of providing a nucleic acid sample comprising a polynucleotide; providing an enzyme to amplify the polynucleotide using an azido nucleotide derivative; amplifying said polynucleotide to provide azido labeled amplified nucleic acids; reacting the azido groups on said nucleic acids with a detectable label to provide labeled nucleic acids; hybridizing said amplified nucleic acids to a nucleic acid array; and detecting the presence or absence of said polynucleotide. Still other methods are presented for detecting polynucleotides on a nucleic acid array using ligases and terminal transferases to end label polynucleotides.
摘要:
In one aspect of the invention, a method is provided for end-labeling RNA (total RNA, mRNA, cRNA or fragmented RNA). In one aspect of the present invention, T4 RNA ligase is used to attach a 3′-labeled AMP or CMP donor to an RNA acceptor molecule. In another embodiment, a pyrophosphate molecule 3′-AppN-3′-linker-detectable moiety is used as donor molecule. In another aspect of the present invention, a method of detecting the presence of an RNA of interest in a sample is provided, the method having the following steps: providing the sample comprising RNA which may or may not have said RNA of interest; treating the sample with a fragmenting reagent to provide RNA fragments; removing phosphate groups from said fragments to provide fragments with free 3′ OH groups; ligating said fragment with a labeling reagent according to the instant invention; providing a nucleic acid array having probes directed to said RNA of interest; hybridizing the labeled nucleic acid fragments to said nucleic acid array; and determining the extent of hybridization to said probes to determine the presence of said RNA of interest.
摘要:
Nucleic acid labeling compounds containing heterocyclic derivatives are disclosed. The heterocyclic derivative containing compounds are synthesized by condensing a heterocyclic derivative with a cyclic group (e.g. a ribofuranose derivative). The labeling compounds are suitable for enzymatic attachment to a nucleic acid, either terminally or internally, to provide a mechanism of nucleic acid detection.
摘要:
The present invention provides a simplified method for identifying differences in nucleic acid abundances (e.g., expression levels) between two or more samples. The methods involve providing an array containing a large number (e.g. greater than 1,000) of arbitrarily selected different oligonucleotide probes where the sequence and location of each different probe is known. Nucleic acid samples (e.g. mRNA) from two or more samples are hybridized to the probe arrays and the pattern of hybridization is detected. Differences in the hybridization patterns between the samples indicates differences in expression of various genes between those samples. This invention also provides a method of end-labeling a nucleic acid. In one embodiment, the method involves providing a nucleic acid, providing a labeled oligonucleotide and then enzymatically ligating the oligonucleotide to the nucleic acid. Thus, for example, where the nucleic acid is an RNA, a labeled oligoribonucleotide can be ligated using an RNA ligase. In another embodiment, the end labeling can be accomplished by providing a nucleic acid, providing labeled nucleoside triphosphates, and attaching the nucleoside triphosphates to the nucleic acid using a terminal transferase.
摘要:
In one aspect of the present invention polymers are used to create films providing three-dimensional array substrates. The films were stable and presented good hydroxyl group numbers as compared with arrays without polymer films. It is an object of the present invention that three dimensional arrays substrates provide a means to obtain higher density polymer arrays.
摘要:
In accordance with the present invention, method are presented for labeling a cDNA strand with a photochemical cleavable reagent which upon exposure to electromagnetic radiation of particular reagent to create abasic DNA sites. According to one aspect of the present invention, DNA at the abasic sites, also known a chemical lactone group, is cleaved with an endonuclease, for example an endonuclease IV, which cleaves the DNA and leaves a free 3′ OH group. This free 3′ OH group is then labeled with a terminal transferase to provide a detectable moiety. In accordance with a preferred aspect of the present invention,
摘要:
Methods for fragmenting and labeling nucleic acids for hybridization analysis are disclosed. In one aspect of the invention, methods and compositions are provided for fragmenting nucleic acid samples by exposure to acidic conditions to generate abasic positions and then cleavage of the abasic sites by, for example, an apurinic/apyrimidinic endonuclease. The resulting fragments may be end labeled and analyzed by hybridization to an array of nucleic acid probes.
摘要:
Methods are provided for post incorporation labeling of a nucleic acid, including for example cRNA, labeled with nucleotide analogs having a formula selected from the group consisting of wherein A is H or a functional group that permits the attachment of the nucleic acid labeling compound to a nucleic acid; Y and Z are independently H or OH; L is linker group; and P is a connecting group. After incorporation of the nucleic acid (including cRNA) with the above nucleotide analogs, the nucleic acid is labeled with a detectable group reagent wherein said detetable group reagent comprises a chemical moiety which is capable of specifically reacting with said P group to allow coupling of the detectable group to said primed cRNA. Compounds comprising nucleotide analogs are also presented in accordance with the present invention. Methods are also presented for incorporating these compounds into nucleic acids and subsequently labeling the incorporated nucleotide analog with detectable moiety reagent.