Spatially encoded biological assays
The present invention provides assays and assay systems for use in spatially encoded biological assays. The invention provides an assay system comprising an assay capable of high levels of multiplexing where reagents are provided to a biological sample in defined spatial patterns; instrumentation capable of controlled delivery of reagents according to the spatial patterns; and a decoding scheme providing a readout that is digital in nature.
1. A method of spatially tagging a target nucleic acid in a tissue sample, the method comprising:
(a) contacting the tissue sample with a plurality of probes, wherein a probe of the plurality of probes comprises: (i) a nucleic acid sequence that hybridizes to at least a portion of the target nucleic acid and (ii) a nucleic acid sequence that hybridizes to at least a portion of an encoding agent;
(b) contacting the tissue sample with a plurality of encoding agents, wherein the encoding agent of the plurality of encoding agents comprises a nucleic acid sequence identifying a spatial location to where the encoding agent was delivered and a nucleic acid sequence that hybridizes to at least a portion of the probe; and
(c) coupling the probe to the encoding agent, thereby generating a nucleic acid molecule comprising the sequence that hybridizes to the target nucleic acid and the nucleic acid sequence identifying the spatial location to where the encoding agent was delivered, thereby spatially tagging the target nucleic acid in the tissue sample.
2. The method of claim 1 , wherein coupling the probe to the encoding agent comprises ligation.
3. The method of claim 2 , wherein the ligation comprises the use of a ligase.
4. The method of claim 1 , wherein the nucleic acid sequence identifying the spatial location to where the encoding agent was delivered identifies a spatial location in the tissue sample to which the encoding agent was delivered.
5. The method of claim 1 , further comprising:
(d) contacting the tissue sample with a second plurality of encoding agents, wherein a second encoding agent of the second plurality of encoding agents comprises a nucleic acid sequence identifying a spatial location to where the second encoding agent was delivered; and
(e) coupling the second encoding agent to the nucleic acid molecule, thereby producing a second nucleic acid molecule comprising the nucleic acid sequence that hybridizes to the target nucleic acid, the nucleic acid sequence identifying the spatial location to where the encoding agent was delivered, and the nucleic acid sequence identifying the spatial location to where the second encoding agent was delivered.
6. The method of claim 5 , wherein coupling the second encoding agent to the nucleic acid molecule comprises ligation.
7. The method of claim 6 , wherein the ligation comprises the use of a ligase.
8. The method of claim 1 , wherein the target nucleic acid is DNA.
9. The method of claim 8 , wherein the DNA is genomic DNA.
10. The method of claim 1 , wherein the target nucleic acid is RNA.
11. The method of claim 10 , wherein the RNA is mRNA.
12. The method of claim 1 , wherein the tissue sample comprises a tissue section.
13. The method of claim 12 , wherein the tissue section is a fresh, frozen tissue section.
14. The method of claim 12 , wherein the tissue section is a fixed tissue section.
15. The method of claim 14 , wherein the fixed tissue section is a formalin-fixed, paraffin-embedded tissue section.
16. The method of claim 1 , wherein the tissue sample is affixed to a support.
17. The method of claim 16 , wherein the support is a slide or a culture dish.
18. The method of claim 5 , wherein the nucleic acid sequence identifying the spatial location to where the second encoding agent was delivered identifies a spatial location in the tissue sample to which the second encoding agent was delivered and wherein the nucleic acid sequence identifying the spatial location to where the second encoding agent was delivered is different than the nucleic acid sequence identifying the spatial location to where the encoding agent was delivered.
19. The method of claim 1 , wherein the nucleic acid sequence that hybridizes to at least a portion of the encoding agent comprises a ligation region.
20. The method of claim 1 , wherein the method further comprises imaging the tissue sample to identify a region of interest in the tissue sample.
21. The method of claim 20 , wherein imaging comprises immunohistochemistry or staining.
22. The method of claim 20 , wherein the method further comprises identifying two or more regions of interest in the tissue sample.
23. The method of claim 1 , wherein:
step (a) comprises selectively delivering to a region of interest in the tissue sample the plurality of probes; and
step (b) comprises selectively delivering to the region of interest in the tissue sample the plurality of encoding agents.
24. The method of claim 23 , wherein the method further comprises coupling the encoding agent to the probe, and wherein the coupling comprises ligation.
25. The method of claim 24 , wherein the ligation comprises the use of a ligase.
26. The method of claim 23 , wherein the encoding agent comprises a nucleic acid sequence identifying a location in the tissue sample to which the encoding agent was delivered.
27. The method of claim 23 , wherein the method further comprises:
(d) selectively delivering to the region of interest in the tissue sample a second plurality of encoding agents, wherein a second encoding agent of the second plurality of encoding agents comprises a nucleic acid sequence identifying a spatial location where the second encoding agent was delivered; and
(e) coupling the second encoding agent to the nucleic acid molecule, thereby producing a second nucleic acid molecule comprising the nucleic acid sequence that hybridizes to at least a portion of the target nucleic acid, the nucleic acid sequence identifying the spatial location to where the encoding agent was delivered, and the nucleic acid sequence identifying the spatial location to where the second encoding agent was delivered.
28. The method of claim 27 , wherein coupling the second encoding agent to the nucleic acid molecule comprises ligation.
29. The method of claim 28 , wherein the ligation comprises the use of a ligase.
30. The method of claim 29 , wherein the second encoding agent identifies a spatial location in the tissue sample to which the second encoding agent was delivered and wherein the nucleic acid sequence identifying the spatial location to where the second encoding agent was delivered is different than the nucleic acid sequence identifying the spatial location to where the encoding agent was delivered.