The La antigen shuttles between the nucleus and the cytoplasm in CV-1 cells

Summary Recently we established a monoclonal antibody against the La-protein (Bachmannet al., Proc. Natl. Acad. Sci. USA, 83, 7770, 1986). The antibody gives a nuclear speckled type staining and, in addition, a perinuclear cytoplasmic staining on cultured cells in immunofluorescence microscopy. After inhibition of RNA synthesis the La-protein is transported into the cytoplasm. After prolonged inhibition it returns into the nucleus forming large growing speckles. The transport into the nucleus apparently depends on glycosylation.Abbreviations FITC Fluorescein Isothiocyanate - RITC Rhodamine Isothiocyanate - scRNP small cytoplasmic Ribonucleoprotein - snRNP Small nuclear Ribonucleoprotein - mab Monoclonal antibody - Ig Immunoglobulin - BSA Bovine Serum Albumin - PBS Phosphate Buffered Saline - PMSF Phenylmethanesulfonyl Fluoride - SDS Sodium Dodecyl Sulfate - EGTA Ethyleneglycol bis(-aminoethyl ether)-N,N,N,N-tetraacetic Acid - MCTD Mixed Connective Tissue Disease - SLE Systemic Lupus Erythematosus