Author Correction: High-throughput single-cell activity-based screening and sequencing of antibodies using droplet microfluidics.

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High-throughput single-cell activity-based screening and sequencing of antibodies using droplet microfluidics.

Mining the antibody repertoire of plasma cells and plasmablasts could enable the discovery of useful antibodies for therapeutic or research purposes1. We present a method for high-throughput, single-cell screening of IgG-secreting primary cells to characterize antibody binding to soluble and membrane-bound antigens. CelliGO is a droplet microfluidics system that combines high-throughput screening for IgG activity, using fluorescence-based in-droplet single-cell bioassays2, with sequencing of paired antibody V genes, using in-droplet single-cell barcoded reverse transcription. We analyzed IgG repertoire diversity, clonal expansion and somatic hypermutation in cells from mice immunized with a vaccine target, a multifunctional enzyme or a membrane-bound cancer target. Immunization with these antigens yielded 100-1,000 IgG sequences per mouse. We generated 77 recombinant antibodies from the identified sequences and found that 93% recognized the soluble antigen and 14% the membrane antigen. The platform also allowed recovery of ~450-900 IgG sequences from ~2,200 IgG-secreting activated human memory B cells, activated ex vivo, demonstrating its versatility.

High-performance chemical- and light-inducible recombinases in mammalian cells and mice.

Site-specific DNA recombinases are important genome engineering tools. Chemical- and light-inducible recombinases, in particular, enable spatiotemporal control of gene expression. However, inducible recombinases are scarce due to the challenge of engineering high performance systems, thus constraining the sophistication of genetic circuits and animal models that can be created. Here we present a library of >20 orthogonal inducible split recombinases that can be activated by small molecules, light and temperature in mammalian cells and mice. Furthermore, we engineer inducible split Cre systems with better performance than existing systems. Using our orthogonal inducible recombinases, we create a genetic switchboard that can independently regulate the expression of 3 different cytokines in the same cell, a tripartite inducible Flp, and a 4-input AND gate. We quantitatively characterize the inducible recombinases for benchmarking their performances, including computation of distinguishability of outputs. This library expands capabilities for multiplexed mammalian gene expression control.

CK2 in Cancer: Cellular and Biochemical Mechanisms and Potential Therapeutic Target.

CK2 genes are overexpressed in many human cancers, and most often overexpression is associated with worse prognosis. Site-specific expression in mice leads to cancer development (e.g., breast, lymphoma) indicating the oncogenic nature of CK2. CK2 is involved in many key aspects of cancer including inhibition of apoptosis, modulation of signaling pathways, DNA damage response, and cell cycle regulation. A number of CK2 inhibitors are now available and have been shown to have activity against various cancers in vitro and in pre-clinical models. Some of these inhibitors are now undergoing exploration in clinical trials as well. In this review, we will examine some of the major cancers in which CK2 inhibition has promise based on in vitro and pre-clinical studies, the proposed cellular and signaling mechanisms of anti-cancer activity by CK2 inhibitors, and the current or recent clinical trials using CK2 inhibitors.

Mining CK2 in cancer.

Cancer is a leading cause of death worldwide. Cancer cells proliferate uncontrollably and, many cases, spread to other parts of the body. A protein historically involved in cancer is protein kinase CK2. CK2 is a serine-threonine kinase that has been involved in cell growth, cell proliferation and cell apoptosis. CK2 functions as an oncogene when overexpressed in mouse tissues, and can synergize with known oncogenes, such as ras, to induce cell transformation in cells in culture. CK2, typically the CK2α protein, is found elevated in a number of human tumors. However, we have little information on CK2α' and CK2ß proteins, and scarce information on CK2 gene transcript expression. Here, we explore the expression of CK2 transcripts in primary tumor tissues using the database Oncomine in the six cancers with the highest mortality in the U.S.A. In addition, we studied the correlation between CK2 expression and overall survival using the Kaplan-Meier Plotter database in breast, ovarian, and lung cancers. We found widespread upregulation in the expression of CK2 genes in primary tumor tissues. However, we found underexpression of CK2α' transcripts in some tumors, increased CK2ß transcripts in some invasive tumors, and deregulation of CK2 transcripts in some tumor precursors. There was also correlation between CK2 expression levels and patient survival. These data provides additional evidence for CK2 as a biomarker for cancer studies and as a target for cancer therapy.