Cytoplasmic accumulation of the 52 kDa RO/SS-A nuclear autoantigen in transfected cell lines

Abstract

The 60 kDa Ro/SS-A (Ro60) autoantigen is thought to reside predominantly in the nucleus; however, the intracellular localization of 52 kDa Ro/SS-A (Ro52) in normal cells is controversial, probably due to its low abundance. Therefore, we studied the intracellular expression and localization of the human Ro52 following transfection of a human Ro52 cDNA into cultured cell lines. Immunofluorescence staining of human (HEp-2) and mouse (LTA-5) cell transfectants with affinity-purified anti-Ro52 antibodies revealed that Ro52 antigen was most abundant in the cytoplasm and present to a lesser extent in the nucleus. This relative localization was supported by a preponderance of the Ro52 antigen in the..