Zeneca Limited

University of Strathclyde

David Mark Whitcombe

Stephen Little

William Ewen Smith

Duncan Graham

Jannine Brownie

Neil James Gibson

Jane Theaker

Disclosed are methods for determining the presence or absence of a target nucleic acid (e.g. DNA) sequence in a sample nucleic acid, the method comprising: (a) exposing the sample to a detection agent comprising a colloid metal surface associated with a SER(R)S active species (SAS) such as an azo dye and with a target binding species (TBS) which may be PNA which is complementary to the target, and (b) observing the sample agent mixture using SER(R)S to detect any surface enhancement of the label wherein the binding of the TBS to the target sequence causes surface enhancement SAS. The detection agent may be exposed to the sample in step (a) as two or more separate components and will generally comprise a first agent and a second agent each having a different TBS, each TBS being capable of binding to the target sequence, and wherein the binding of the first and second TBS to the target sequence brings a metal surface associated with each TBS into proximity thereby causing surface enhancement of an SAS associated with one or both of the metal surfaces.

Nucleic acid sequence identification

A method for the detection of a target nucleic acid, which method comprises contacting template nucleic acid from a sample with (i) a signalling system and (ii) a tailed nucleic acid primer having a template binding region and the tail comprising a linker and a target binding region, in the presence of appropriate nucleoside triphosphates and an agent for polymerization thereof, under conditions such that the template binding region of the primer will hybridize to a complementary sequence in the template nucleic acid and be extended to form a primer extension product, separating any such product from the template whereupon the target binding region in the tail of the primer will hybridize to a sequence in the primer extension product corresponding to the target nucleic acid, and wherein any such target specific hybridization causes a detectable change in the signalling system, such that the presence or absence of the target nucleic acid in the sample is detected by reference to the presence or absence of a detectable change in the signalling system.

Methods for detecting target nucleic acid sequences

A method for the detection of diagnostic base sequences in a sample nucleic acid comprises contacting the sample in the presence of appropriate nucleoside triphosphates and an agent for polymerization thereof with a diagnostic primer for the diagnostic base sequence, the primer having a tail sequence comprising a tag region and a detector region such that an extension product of the primer is synthesized when the corresponding base sequence is present in the sample, and any extension product of the diagnostic primer acting as a template for extension of a further primer which hybridizes to a locus at a distance from the diagnostic base sequence. The sample is contacted with a tag primer which selectively hybridizes to the complement of the tag sequence in an extension product of the further primer and is extended, and the presence or absence of the diagnostic base sequence is detected by reference to the detector region in the further primer extension product.

Method for detecting a nucleic acid base sequence

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Northwich, United Kingdom

David Mark Whitcombe