Methods for spatial analysis using RNA-templated ligation
Provided herein are methods of detecting an analyte of interest to interrogate spatial gene expression in a sample using RNA-templated ligation.
1. A method for determining a location of a target nucleic acid in a biological sample comprising:
(a) providing an array comprising a plurality of capture probes affixed to the array, wherein a capture probe of the plurality of capture probes comprises: (i) a spatial barcode and (ii) a capture domain;
(b) contacting a plurality of first probes and second probes to a biological sample on the array, wherein the plurality of first probes and second probes target a plurality of nucleic acids in the biological sample and wherein a first probe and a second probe of the plurality comprise sequences that are substantially complementary to the target nucleic acid, and wherein the second probe comprises a capture probe capture domain sequence that is complementary to all or a portion of the capture domain of the capture probes affixed to the array;
(c) hybridizing the first probe and the second probe to the target nucleic acid;
(d) generating a ligation product by ligating the first probe and the second probe;
(e) releasing the ligation product from the target nucleic acid;
(f) hybridizing the ligation product to the capture domain of the capture probe affixed on the array; and
(g) determining (i) all or part of the sequence of the ligation product bound to the capture domain, or a complement thereof, and (ii) the sequence of the spatial barcode, or a complement thereof, and using the determined sequences of (i) and (ii) to determine the location of the target nucleic acid in the biological sample.
2. The method of claim 1 , wherein the first probe and the second probe are substantially complementary to adjacent sequences of the target nucleic acid.
3. The method of claim 1 , where the first probe and the second probe hybridize to sequences that are not adjacent to each other on the target nucleic acid.
4. The method of claim 3 , wherein the first probe is extended with a DNA polymerase, thereby (i) filling in a gap between the first probe and the second probe and (ii) generating an extended first probe.
5. The method of claim 1 , further comprising (i) hybridizing the first probe and the second probe to the target nucleic acid at a temperature from about 50° C. to about 75° C., and (ii) hybridizing the first probe and the second probe to a third probe at a temperature from about 15° C. to about 35° C.
6. The method of claim 1 , wherein the contacting the first probe and the second probe with the biological sample comprises contacting the biological sample with 5000 or more probe pairs, wherein a probe pair of the 5000 or more probe pairs comprises the first probe and the second probe.
7. The method of claim 1 , wherein the generating the ligation product comprises ligating the first probe to the second probe using enzymatic ligation or chemical ligation, wherein the enzymatic ligation utilizes a ligase.
8. The method of claim 4 , wherein the generating the ligation product comprises ligating the extended first probe to the second probe using enzymatic ligation or chemical ligation, wherein the enzymatic ligation utilizes a ligase.
9. The method of claim 7 , wherein the ligase is one or more of a T4 RNA ligase (Rnl2), a splintR ligase, a single stranded DNA ligase, or a T4 DNA ligase.
10. The method of claim 1 , wherein the first probe further comprises a primer sequence.
11. The method of claim 1 , further comprising providing a capture probe capture domain blocking moiety that interacts with the capture probe capture domain sequence.
12. The method of claim 11 , further comprising releasing the capture probe capture domain blocking moiety from the capture probe capture domain sequence prior to step (f).
13. The method of claim 11 , wherein the capture probe capture domain sequence comprises a poly-adenylated sequence or a complement thereof, and the capture probe capture domain blocking moiety comprises a poly-uridine sequence, a poly-thymidine sequence, or both.
14. The method of claim 1 , wherein the first probe and/or the second probe is a DNA probe.
15. The method of claim 11 , wherein the capture probe capture domain blocking moiety is a DNA probe.
16. The method of claim 12 , wherein the releasing the capture probe capture domain blocking moiety from the capture probe capture domain sequence comprises contacting the biological sample with an endoribonuclease.
17. The method of claim 1 , wherein the releasing the ligation product from the target nucleic acid comprises contacting the biological sample with an endoribonuclease.
18. The method of claim 17 , wherein the endoribonuclease is an RNase H enzyme.
19. The method of claim 1 , wherein the biological sample is a tissue sample.
20. The method of claim 19 , wherein the tissue sample is a formalin-fixed, paraffin-embedded tissue sample, a fresh tissue sample, or a frozen tissue sample.
21. The method of claim 19 , wherein the tissue sample is a formalin-fixed, paraffin-embedded tissue sample.
22. The method of claim 1 , wherein the biological sample was previously stained using immunofluorescence, immunohistochemistry, or hematoxylin and eosin.
23. The method of claim 1 , further comprising contacting the biological sample with a permeabilization agent, wherein the permeabilization agent is selected from an organic solvent, a detergent, an enzyme, or a combination thereof.
24. The method of claim 23 , wherein the permeabilization agent comprises proteinase K or pepsin.
25. The method of claim 1 , wherein the target nucleic acid comprises RNA.
26. The method of claim 25 , wherein the RNA is an mRNA.
27. The method of claim 1 , wherein the determining step (g) comprises amplifying all or part of the ligation product, thereby generating an amplified product, and wherein the amplified product comprises (i) all or part of sequence of the ligation product, or a complement thereof, and (ii) the sequence of the spatial barcode, or a complement thereof.
28. The method of claim 1 , wherein the determining step (g) comprises sequencing (i) all or a part of the sequence of the ligation product, or a complement thereof, and (ii) the sequence of the spatial barcode, or a complement thereof.
29. The method of claim 28 , wherein the sequencing comprises in situ sequencing, Sanger sequencing methods, and next-generation sequencing methods.
30. The method of claim 1 , wherein the contacting the first probe and the second probe with the biological sample comprises contacting the biological sample with 100 or more probe pairs, wherein a probe pair of the 100 or more probe pairs comprises the first probe and the second probe.