Abstract: Among other things, this disclosure provides a method of detecting a target nucleic acid. Aspects of the method include: (a) obtaining a labeled nucleic acid probe that is complementary to a target nucleic acid, wherein the probe comprises a capture tag; (b) hybridizing the probe with the target nucleic in a fixed cell, in situ, to produce a duplex; (c) linking the probe in the duplex to a peroxidase conjugate via the capture tag to produce a peroxidase-labeled duplex; and (d) incubating the peroxidase-labeled duplex with a peroxidase substrate, wherein the peroxidase activity of the peroxidase conjugate catalyzes deposition of the substrate in the vicinity of the duplex, thereby producing a detectable signal.

Abstract: Among other things, this disclosure provides a method of detecting a target nucleic acid. Aspects of the method include: (a) obtaining a labeled nucleic acid probe that is complementary to a target nucleic acid, wherein the probe comprises a capture tag; (b) hybridizing the probe with the target nucleic in a fixed cell, in situ, to produce a duplex; (c) linking the probe in the duplex to a peroxidase conjugate via the capture tag to produce a peroxidase-labeled duplex; and (d) incubating the peroxidase-labeled duplex with a peroxidase substrate, wherein the peroxidase activity of the peroxidase conjugate catalyzes deposition of the substrate in the vicinity of the duplex, thereby producing a detectable signal.

Abstract: A composition comprising population of labeled oligonucleotides is provided herein. In some embodiments, the probes are of the formula: T1-V-T2, wherein: the nucleotide sequence of the V region varies in said population; the V regions of the different oligonucleotides hybridize to sites that are tiled across a sequence in a target nucleic acid; the T1 and T2 regions do not hybridize with said target nucleic acid; within each oligonucleotide of the population, the T1 and T2 regions are not complementary; and within each oligonucleotide of the population, the T1 region is complementary to the T2 region of at least one of other oligonucleotide of the population. Also provided is a method that comprises hybridizing the population of labeled oligonucleotides with a target nucleic acid to produce a complex.

Abstract: Provided herein is a proximity assay that, in certain embodiments, involves: (a) hybridizing a first oligonucleotide and a second oligonucleotide with a target nucleic acid, wherein the first oligonucleotide comprises: i. a region that is complementary to a first sequence in the target nucleic acid and ii. a barcode sequence; and the second oligonucleotide comprises i. a region that is complementary to a second region in the target and ii. the complement of the barcode sequence; and (b) detecting hybridization between the barcode sequence and the complement of the barcode sequence, wherein hybridization between the barcode sequence and the complement of the barcode sequence indicates that the first and second target sequences are proximal to one another in the sample.