Identification of a novel Dlg2 isoform differentially expressed in IFN?-producing plasmacytoid dendritic cells.

ABSTRACT: BACKGROUND:The murine discs large homolog 2 (DLG2; post synaptic density 93 (PSD-93); Chapsyn-110) is a member of the membrane-associated guanylate kinase (MAGUK) protein family involved in receptor assembly and associated with signaling enzymes on cell membranes. In neurons, DLG2 protein isoforms derived from alternatively spliced transcripts have been described to bind to NMDA (N-methyl-aspartate) receptors and K channels and to mediate clustering of these channels in the postsynaptic membrane. In myeloid cells of the immune system, such as dendritic cells (DCs), a lack of data exists on the expression or function of DLG2. In cDNA microarray transcriptome analyses, we found Dlg2 highly expressed in a subpopulation of plasmacytoid DCs (pDCs) stimulated to produce type I interferons (IFNs) such as IFN?. RESULTS:Using RACE- and RT-PCR as well as immunoprecipitation followed by Western blotting we characterised the differential expression of the Dlg2 splice variants in IFN?-producing pDCs. Besides Dlg2? this cell population expressed a novel short Dlg2? transcript we termed Dlg2?3. Our expression data were integrated into information from genome databases to obtain a novel and comprehensive overview of the mouse Dlg2 gene architecture. To elucidate the intracellular localisation pattern of protein isoforms, ectopical expression analysis of fluorescently tagged DLG2 splice variants was performed. Here we found an enrichment of the larger isoform DLG2?1 at the plasma membrane while the newly identified shorter (DLG2?) isoform as well as DLG2? were equally distributed throughout the cytoplasm. Additionally, DLG2? was also found in the nucleus. Analysis of Dlg2-knockout mice previously generated by deleting exon 9 surprisingly revealed that the protein for the novel DLG2? isoform was still expressed in the brain and in bone marrow-derived pDCs from mice carrying the homozygous deletion (Dlg2 ?E9/?E9 ). CONCLUSION:We describe a novel splice variant of the mouse Dlg2 gene termed Dlg2? and define the differential expression pattern of DLG2 isoforms in IFN?-producing pDCs. The presence of DLG2? protein in the CNS of Dlg2 ?E9/?E9 mice might influence the phenotype of these mice and has to be taken into account in the interpretation of results regarding the functional role of DLG2 in neuronal postsynaptic membranes.

SUBMITTER: Ali S 

PROVIDER: S-EPMC6389146 | biostudies-literature | 2018 Mar

REPOSITORIES: biostudies-literature