Nuclear dot antigens may specify transcriptional domains in the nucleus.

Abstract

A bank of 892 human autoimmune serum samples was screened by indirect immunofluorescence on human tissue culture A wide variety of cellular processes occur within the nucleus, including DNA replication, RNA transcription and processing, and ribosome biogenesis (18,33). Some of these activities are carried out in distinct regions of the nucleus; ribosome biogenesis occurs within the nucleolus (13), splicing complexes are organized into splicing domains (14, 17), and DNA replication occurs at discrete sites (15). Other less well-characterized regions of the nucleus have also been described, including nuclear bodies, which appear as granular fibrils defining the space between perichromatin and perinuclear chromatin (7, 52), and polymorphic interphase karyosomal associations, which appear as nuclear domains that are very heterogeneous in size and number from one cell to the next (42). To what extent other morphological domains exist in the nucleus and whether they carry out distinct cellular functions are not known.One method to determine whether specific subcellular domains exist within the mammalian nucleus is to screen sera from autoimmune disease patients for antibodies that recognize novel staining patterns. Patients with specific autoimmune diseases often contain antibodies directed to nuclear components (10,27,51). These include antibodies directed to kinetochores (5, 12, 20, 32), nuclear lamins (24, 37), topoisomerase I (29), proliferating-cell nuclear antigen (4,28,36), and splicing components (26,34,38). One unusual type of autoantibody recognizes speckled dots or nuclear dots (NDs) (2, 6, 39), which are visible as approximately six brightly staining dots in the nucleus.In this report, we describe autoantibodies directed to a 72,000-Mr ND antigen. The ND domain is distinct from known nuclear domains such as splicing centers or kinetochores. Cloning and molecular characterization of a major ND antigen are also reported. In the course of our studies, * Corresponding author. reports from two other laboratories have partially described ND antigens (2, 50). Our results indicate that the 72-kDa ND antigen is associated with nuclear DNA and can serve as a transcriptional activator in Saccharomyces cerevisiae and mammalian cells. MATERIALS AND METHODSStrains and sera. Human autoimmune sera were provided by J. Hardin and J. Craft of the Yale University School of Medicine and screened as described by Yang et al. (56

Arsenic-induced PML targeting onto nuclear bodies: Implications for the treatment of acute promyelocytic leukemia

“…As these images are also observed in spontaneously apoptotic NB4 cells (ref. 27 and data not shown), we investigated the earlier effects of arsenic (at the therapeutic concentration of 10 Ϫ6 M) on the localization of the NB antigens [PML, Sp100 (12,13), and NDP52 (17)] as well as PML͞ RAR␣. As 2 O 3 profoundly affected the immunofluorescence pattern obtained with an anti-PML antisera that detects both PML and PML͞RAR␣.…”

“…For example, arsenic recruits Sp100 onto NBs but fails to degrade this protein. Should Sp100 exert some functions out of NB (such as transcriptional activation (12,13)), arsenic-induced Sp100 sequestration would then abolish it.…”

“…These structures (which belong to the nuclear matrix; ref. 10) were previously identified using autoantibodies from patients with primary biliary cirrhosis (11) that recognize a proposed transcription factor, Sp100 (12,13). The three NB antigens identified to date, Sp100, PML, and NDP52, are all target genes of interferons (IFNs; refs.…”

Transcriptional regulation in acute promyelocytic leukemia

“…These post-translationally modi®ed factors could then be assembled into higher order complexes to regulate transcription of speci®c genes. Third, the PODs could actually provide a microenvironment of transcriptional activation (LaMorte et al, 1998;Xie et al, 1993) or repression (Lehming et al, 1998), and be places where coregulators could be activated or inhibited (reviewed in Doucas, 2000). At the current stage, it is impossible to cleanly prove or disprove one of these models, and novel techniques examining transcriptional regulation on the level of a single gene locus in vivo need to be developed in order to resolve these issues.…”

SCFCdc4-mediated Degradation of the Hac1p Transcription Factor Regulates the Unfolded Protein Response inSaccharomyces cerevisiae

“…pACT and pBTM116 constructs were transformed into S. cerevisiae strain L40 (Hollenberg et al, 1995). Protein-protein interaction assays were performed by growing transformants on nitrocellulose filters before lysing the cells and measuring ␤-galactosidase activity as described by Xie et al (1993). …”