Simultaneous detection of target protein and target nucleic acids in a single cell

A method of detecting an RNA and a protein in a sample, the method comprising:

• (a) incubating a sample in a reaction mixture with a pair of protein-detecting proximity probes comprising a first and a second protein detecting proximity probe where:
• the first protein-detecting probe comprises a first antibody that binds to the target protein joined to a first polynucleotide that comprises an I segment at the 3′ end that is complementary to an I segment on the 3′ end of the second probe;
• and
• the second protein-detecting probe comprises a second antibody that binds to the target protein joined to a second polynucleotide that comprises an I segment complementary to the I segment at the 3′ end of the first polynucleotide;
• wherein binding of the first antibody to the target protein and binding of the second antibody to the target protein allows the I segment of the first protein proximity probe to hybridize to the I segment of the second protein proximity probe to form a duplex;
• (b) extending the duplex using a DNA polymerase to provide an extended product
• (c) amplifying the extended product, or a subregion thereof, using a set of primers that amplify the extended product or subregion thereof;
• and
• (d) detecting an RNA of interest in the sample and the amount of amplicon from amplification of the extended product or subregion thereof.