Provided herein are methods and composition for immune repertoire sequencing and single cell barcoding. In some aspects, such methods may comprise steps of: (a) forming a plurality of vessels each comprising a first cell cDNA of a first cell polynucleotide from a single cell and a second cell cDNA of a second cell polynucleotide from the single cell; (b) extending the first cell cDNA that is hybridized to a barcoded polynucleotide comprising a primer binding site sequence and a barcode sequence and a cDNA annealing sequence, or an amplicon thereof; and extending the second cell cDNA that is hybridized to a barcoded polynucleotide comprising a primer binding site sequence and the barcode sequence and a cDNA annealing sequence, or an amplicon thereof; and (c) amplifying the extended first cell cDNA and the extended second cell cDNA with a primer set.

A combined ribosome-display and phage-display method and kit for carrying out the method are provided. The method includes screening a ribosome-display library of binding agents to identify binding agents that interact with one or more target molecules of interest, converting the RNA encoding the binding agents to a phage-display format by amplification and primer extension, and the screening the phage-display library to enrich for binding agents that interact with one or more target molecules of interest.

Molecules of general Formula (I): able to bind to native polyribosomes engaged in active protein synthesis. The disclosure relates also to the use of the molecules of general Formula (I) for isolating at least one active ribosome from a biological sample, and for ribosome profiling, as well as kits for isolating at least one active ribosome from a biological sample.

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Provided herein are methods and composition for immune repertoire sequencing and single cell barcoding. In some aspects, such methods may comprise steps of: (a) forming a plurality of first vessels each comprising: (i) a single cell, and (ii) a single solid support; (b) copying onto the single solid support: (i) a first copy of a first cell polynucleotide from the single cell, and (ii) a second copy of a second cell polynucleotide from the single cell; (c) forming a plurality of second vessels each comprising (i) a single solid support from the plurality of first vessels, and (ii) a barcoded polynucleotide; and (d) amplifying (i) the first copy and the second copy with a first primer set, and (ii) the barcode with a second primer set, wherein a primer of the first primer set is complementary to a primer of the second set; and (e) forming first and second single cell barcoded sequences.

A novel method for displaying proteins and peptides is disclosed in which individual proteins or peptides remain associated with the DNA encoding them. Proteins or peptides can be generated by in vitro translation of DNA templates, either free in solution or arrayed on a solid support, such that the proteins or peptides remain immobilized on their DNA templates. In particular, high throughput sequencing can be combined with high throughput functional characterization of encoded proteins and peptides, wherein the identity of each protein or peptide is determined by DNA sequencing, and functional studies are carried out directly on each protein or peptide while immobilized on the DNA template encoding it. The methods of the invention should find numerous applications, for example, in high throughput genetic or pharmacological screening, epitope mapping, and protein engineering and directed evolution.

Methods and systems for increasing the stability of a nucleic acid template that encodes a protein of interest in a cell free translation system or a ribosomal display reaction system are described. In some embodiments, the nucleic acid template is an RNA or mRNA. The stability of the RNA template is increased by adding the bacteriophage lambda protein Gam to the cell free extract used in the translation system. The addition of Gam protein increases the longevity of the reaction system, thereby increasing the efficiency of the ribosomal display reaction system.

Provided herein are methods and composition for immune repertoire sequencing and single cell barcoding. In some aspects, such methods may comprise steps of: (a) forming a plurality of first vessels each comprising: (i) a single cell, and (ii) a single solid support; (b) copying onto the single solid support: (i) a first copy of a first cell polynucleotide from the single cell, and (ii) a second copy of a second cell polynucleotide from the single cell; (c) forming a plurality of second vessels each comprising (i) a single solid support from the plurality of first vessels, and (ii) a barcoded polynucleotide; and (d) amplifying (i) the first copy and the second copy with a first primer set, and (ii) the barcode with a second primer set, wherein a primer of the first primer set is complementary to a primer of the second set; and (e) forming first and second single cell barcoded sequences.

Methods and systems for increasing the stability of a nucleic acid template that encodes a protein of interest in a cell free translation system or a ribosomal display reaction system are described. In some embodiments, the nucleic acid template is an RNA or mRNA. The stability of the RNA template is increased by adding the bacteriophage lambda protein Gam to the cell free extract used in the translation system. The addition of Gam protein increases the longevity of the reaction system, thereby increasing the efficiency of the ribosomal display reaction system.

The present invention relates to a method of identifying a protein that binds to a target molecule and has intracellular functionality. This method includes providing a construct comprising a deoxyribonucleic acid molecule encoding the protein which binds to the target molecule, with the deoxyribonucleic acid molecule being coupled to a stall sequence. A host cell is transformed with the construct and then cultured under conditions effective to form, within the host cell, a complex of the protein whose translation has been stalled, the mRNA encoding the protein, and ribosomes. The protein in the complex is in a properly folded, active form and the complex is recovered from the cell.

The polynucleotide construct of (1) or (2) below is used to perform ribosome display, CIS display and/or mRNA display in order to screen a Fab against an antigen of interest: (1) a polynucleotide construct which monocistronically comprises a ribosome-binding sequence, Fab first chain-coding sequence, linker peptide-coding sequence, Fab second chain-coding sequence and scaffold-coding sequence in this order, and further comprises at its 3-end a structure necessary for maintaining a complex with the Fab encoded by itself; and (2) a polynucleotide construct which comprises a Fab first chain-expressing cistron and a Fab second chain-expressing cistron each containing a ribosome-binding sequence, a Fab first chain-coding sequence or Fab second chain-coding sequence, and a scaffold-coding sequence in this order, the first Fab-expressing cistron further comprising at its 3-end a ribosome stall sequence, said Fab second chain-expressing cistron further comprising at its 3-end a structure necessary for maintaining a complex with the Fab encoded by itself.