Fibrillarin: a new protein of the nucleolus identified by autoimmune sera.

摘要: Autoimmune serum from a patient with scleroderma was shown by indirect immunofluorescence to label nucleoli in variety of cells tested including: rat kangaroo PtK2, Xenopus A6, 3T3, HeLa, and human peripheral blood lymphocytes. Immunoblot analysis nucleolar proteins the antibody resulted labeling single protein band 34 kD molecular weight pI 8.5. Electron microscopic immunocytochemistry demonstrated that recognized antiserum localized exclusively fibrillar region nucleolus which included both dense center regions. Therefore, we have named this "fibrillarin". Fibrillarin found on putative chromosomal organizer regions (NORs) metaphase anaphase, during telophase fibrillarin be an early marker for site formation newly forming nucleolus. Double immunoelectron microscopy normal, actinomycin D-segregated, DRB-treated showed B23 were predominantly granular nucleolus, respectively. RNase A DNase I digestion situ partially removed completely DNase. These results suggest is widely occurring basic nonhistone whose location nuclease sensitivity may indicate some structural and/or functional role rDNA-containing