Methods for in situ transcriptomics and proteomics
Disclosed herein, inter alia, are compositions and methods of use thereof for interrogating a cell.
1. A method of detecting a plurality of target RNA molecules comprising different RNA nucleic acid sequences within an optically resolved volume of a cell in situ; said method comprising:
i) hybridizing a padlock probe to two adjacent RNA nucleic acid sequences of each of the plurality of target RNA molecules, wherein the padlock probe is a single-stranded polynucleotide having a 5′ and a 3′ end, and wherein the padlock probe comprises at least two oligonucleotide barcodes and at least two different primer binding sequences, wherein the at least two barcodes are from a known set of barcodes associated with each of the plurality of target RNA molecules;
ii) sequentially sequencing each barcode to obtain a multiplexed signal in the cell in situ;
iii) demultiplexing the multiplexed signal by comparison with the known set of barcodes; and
iv) detecting the plurality of target RNA molecules by identifying the associated barcodes detected in the cell.
2. The method of claim 1 , further comprising ligating the 5′ and 3′ ends of the padlock probe to form a circular polynucleotide.
3. The method of claim 2 , further comprising amplifying the circular polynucleotide by extending an amplification primer with a strand-displacing polymerase, wherein the primer extension generates an extension product comprising multiple complements of the circular polynucleotide.
4. The method of claim 1 , wherein the padlock probe comprises at least 3 different primer binding sequences.
5. The method of claim 1 , wherein the padlock probe comprises 2 to 10 different primer binding sequences.
6. The method of claim 1 , wherein the barcode is at least 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 nucleotides in length.
7. The method of claim 1 , wherein the number of unique targets detected within an optically resolved volume of the cell is about 3, 10, 30, 50, or 100.
8. The method of claim 1 , wherein sequencing comprises extending a sequencing primer to generate a sequencing read comprising the barcode sequence.
9. The method of claim 1 , wherein sequencing comprises (a) extending a sequencing primer by incorporating a labeled nucleotide, or labeled nucleotide analogue and (b) detecting the label to generate a signal for each incorporated nucleotide or nucleotide analogue.
10. The method of claim 9 , wherein the labeled nucleotide or labeled nucleotide analogue further comprises a reversible terminator moiety.
11. The method of claim 9 , wherein detecting comprises two-dimensional (2D) or three-dimensional (3D) fluorescent microscopy.
12. The method of claim 9 , wherein detecting comprises confocal microscopy, light sheet microscopy, structured illumination microscopy, oblique plane microscopy, or multi-photon microscopy.
13. The method of claim 1 , wherein the cell is permeabilized and immobilized to a solid support surface.
14. The method of claim 13 , wherein the surface comprises a patterned surface suitable for immobilization of a plurality of cells in an ordered pattern.
15. The method of claim 1 , wherein the method does not comprise lysing the cell.
16. The method of claim 1 , wherein the optically resolved volume has an axial resolution that is greater than the lateral resolution.
17. The method of claim 1 , wherein barcodes in the known set of barcodes have a specified Hamming distance, wherein the Hamming distance is 1 to 15.
18. The method of claim 1 , wherein demultiplexing the multiplexed signal comprises a linear decomposition of the multiplexed signal.
19. The method of claim 1 , wherein the cell forms part of a tissue in situ.
20. The method of claim 2 , wherein ligating comprises contacting the padlock probe with an RNA-dependent DNA ligase.
21. The method of claim 1 , wherein sequentially sequencing comprises extending a first sequencing primer with labeled nucleotide analogues to generate a first extension strand comprising the complementary sequence of a first barcode, incorporating a dideoxynucleotide triphosphate (ddNTP) into the first sequencing extension strand, and extending a second sequencing primer with labeled nucleotide analogues to generate a second extension strand comprising the complementary sequence of a second barcode.
22. The method of claim 1 , wherein sequentially sequencing comprises extending a first sequencing primer with labeled nucleotide analogues to generate a first extension strand comprising the complementary sequence of a first barcode, removing the first extension strand, and extending a second sequencing primer with labeled nucleotide analogues to generate a second extension strand comprising the complementary sequence of a second barcode.
23. The method of claim 21 , wherein the labeled nucleotide analogues are detected, thereby generating a sequencing read.