Dual ifgMosaic: A Versatile Method for Multispectral and Combinatorial Mosaic Gene-Function Analysis

Improved methods for manipulating and analyzing gene function have provided a better understanding of how genes work during organ development and disease. Inducible functional genetic mosaics can be extraordinarily useful in the study of biological systems; however, this experimental approach is still rarely used in vertebrates. This is mainly due to technical difficulties in the assembly of large DNA constructs carrying multiple genes and regulatory elements and their targeting to the genome. In addition, mosaic phenotypic analysis, unlike classical single gene-function analysis, requires clear labeling and detection of multiple cell clones in the same tissue. Here, we describe several methods for the rapid generation of transgenic or gene-targeted mice and embryonic stem (ES) cell lines containing all the necessary elements for inducible, fluorescent, and functional genetic mosaic (ifgMosaic) analysis. This technology enables the interrogation of multiple and combinatorial gene function with high temporal and cellular resolution.This work was supported by grants to the PI R.B. from the Spanish Ministry of Economy, Industry and Competitiveness (SAF2013-44329-P, SAF2013-42359-ERC, and RYC-2013-13209) and European Research Council (ERC-2014-StG - 638028). S.P.-Q., M.F.-C., and I.G.-G. were supported by PhD fellowships from Fundacion La Caixa (CX-SO-2013-02, CX\_E-2015-01, and CX-SO-16-1, respectively). W.L. by a FP7-PEOPLE-2012-COFUND GA600396 postdoctoral contract. We thank Simon Bartlett for English editing, Ralf H. Adams for sharing the Cdh5(PAC)-CreERT2 mice, Jose Luis de La Pompa for comments throughout the project and for sharing the Tie2-Cre mice, Gonzalo Gancedo for the help with the mouse colony, Valeria Caiolfa for the help with the microscopy, and all the members of the CNIC gene targeting, transgenesis, cellomics, and microscopy units. The CNIC is supported by MEIC/MINECO and the Pro CNIC Foundation and is a Severo Ochoa Center of Excellence (SEV-2015-0505).S

Expanded cells in monoclonal TCR-alpha beta(+)/CD4(+)/NKa(+)/CD8(-/+dim) T-LGL lymphocytosis recognize hCMV antigens

Recent studies suggest the potential involvement of common antigenic stimuli on the ontogeny of monoclonal T-cell receptor (TCR)-alpha beta(+)/CD4(+)/NKa(+)/CD8(-/+dim) T-large granular lymphocyte (LGL) lymphocytosis. Because healthy persons show (oligo) clonal expansions of human cytomegalovirus (hCMV)-specific TCRV beta(+)/CD4(+)/cytotoxic/memory T cells, we investigate the potential involvement of hCMV in the origin and/or expansion of monoclonal CD4(+) T-LGL. Peripheral blood samples from patients with monoclonal TCR-alpha beta(+)/CD4(+) T-LGL lymphocytosis and other T-chronic lymphoproliferative disorders were evaluated for the specific functional response against hCMV and hEBV whole lysates as well as the "MQLIPDDYSNTHSTRYVTVK" hCMV peptide, which is specifically loaded in HLA-DRB1*0701 molecules. A detailed characterization of those genes that underwent changes in T-LGL cells responding to hCMV was performed by microarray gene expression profile analysis. Patients with TCR-alpha beta(+)/CD4(+) T-LGL displayed a strong and characteristic hCMV-specific functional response, reproduced by the hCMV peptide in a subset of HLA-DRB1*0701(+) patients bearing TCRV beta 13.1(+) clonal T cells. Gene expression profile showed that the hCMV-induced response affects genes involved in inflammatory and immune responses, cell cycle progression, resistance to apoptosis, and genetic instability. This is the first study providing evidence for the involvement of hCMV in the ontogeny of CD4(+) T-LGL, emerging as a model disorder to determine the potential implications of quite a focused CD4(+)/cytotoxic immune response. (Blood. 2008; 112: 4609-4616

Pulse oximetry is an essential tool that saves lives: A call for standardisation

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