title: Cytoplasmic Z-RNA.
abstract: Specific immunochemical probes for Z-RNA were generated and characterized to search for possible Z-RNA-like double helices in cells. Z-RNA was detected in the cytoplasm of fixed protozoan cells by immunofluorescence microscopy using these anti-Z-RNA IgGs. In contrast, autoimmune or experimentally elicited anti-DNA antibodies, specifically reactive with B-DNA or Z-DNA, stained the nuclei. Pre-or nonimmune IgGs did not bind to the cells. RNase A or T1 digestion eliminated anti-Z-RNA IgG binding to cytoplasmic determinants; however, DNase I or mung bean nuclease had no effect. Doxorubicin and ethidium bromide prevented anti-Z-RNA antibody binding; however, actinomycin D, which does not bind double-stranded RNA, did not. Anti-Z-RNA immunofluorescence was specifically blocked in competition assays by synthetic Z-RNA but not Z-DNA, A-RNA, or single-stranded RNAs. Thus, some cytoplasmic sequences in fixed cells exist in the left-handed Z-RNA conformation.
mesh_terms: D000818:Animals; D000918:Antibody Specificity; D001665:Binding Sites; D003593:Cytoplasm / Q000378:metabolism; D056890:Eukaryota / Q000378:metabolism; D007120:Immunochemistry; D007136:Immunoglobulins; D009690:Nucleic Acid Conformation; D012313:RNA / Q000276:immunology / Q000378:metabolism*
chemical_list: D007136:Immunoglobulins; D012313:RNA