scholarly journals RGS12TS-S Localizes at Nuclear Matrix-Associated Subnuclear Structures and Represses Transcription: Structural Requirements for Subnuclear Targeting and Transcriptional Repression

2002 ◽  
Vol 22 (12) ◽  
pp. 4334-4345 ◽  
Author(s):  
Tapan K. Chatterjee ◽  
Rory A. Fisher
Keyword(s):  
Cell Cycle ◽  
Nuclear Matrix ◽  
Matrix Protein ◽  
Biological Activities ◽  
Polycomb Group ◽  
Nuclear Bodies ◽  
Regulation Of Transcription ◽  
Independent Manner ◽  
Control Of Gene Expression ◽  
Rgs Protein

ABSTRACT RGS12TS-S, an 1,157-amino-acid RGS protein (regulator of G protein signaling), is a nuclear protein that exhibits a unique pattern of subnuclear organization into nuclear foci or dots when expressed endogenously or ectopically. We now report that RGS12TS-S is a nuclear matrix protein and identify structural determinants that target this protein to the nuclear matrix and to discrete subnuclear sites. We also determine the relationship between RGS12TS-S-decorated nuclear dots and known subnuclear domains involved in control of gene expression and provide the first evidence that RGS12TS-S is functionally involved in the regulation of transcription and cell cycle events. A novel nuclear matrix-targeting sequence was identified that is distinct from a second novel motif needed for targeting RGS12TS-S to nuclear dots. RGS12TS-S nuclear dots were distinct from Cajal bodies, SC-35 domains, promyelocytic leukemia protein nuclear bodies, Polycomb group domains, and DNA replication sites. However, RGS12TS-S inhibited S-phase DNA synthesis in various tumor cell lines independently of Rb and p53 proteins, and its prolonged expression promoted formation of multinucleated cells. Expression of RGS12TS-S dramatically reduced bromo-UTP incorporation into sites of transcription. RGS12TS-S, when tethered to a Gal4 DNA binding domain, dramatically inhibited basal transcription from a Gal4-E1b TATA promoter in a histone deacetylase-independent manner. Structural analysis revealed a role for the unique N-terminal domain of RGS12TS-S in its transcriptional repressor and cell cycle-regulating activities and showed that the RGS domain was dispensable for these functions. These results provide novel insights into the structure and function of RGS12TS-S in the nucleus and demonstrate that RGS12TS-S possesses biological activities distinct from those of other members of the RGS protein family.

CHMP1 is a novel nuclear matrix protein affecting chromatin structure and cell-cycle progression

2001 ◽  
Vol 114 (13) ◽  
pp. 2383-2393 ◽  
Author(s):  
Daniel R. Stauffer ◽  
Tiffani L. Howard ◽  
Thihan Nyun ◽  
Stanley M. Hollenberg
Keyword(s):  
Gene Silencing ◽  
Nuclear Matrix ◽  
Cell Cycle Progression ◽  
Matrix Protein ◽  
Multivesicular Body ◽  
Polycomb Group ◽  
Condensed Chromatin ◽  
Stable Gene ◽  
Body Protein ◽  
Reading Frame

The Polycomb-group (PcG) is a diverse set of proteins required for maintenance of gene silencing during development. In a screen for conserved partners of the PcG protein Polycomblike (Pcl), we have identified a new protein, human CHMP1 (CHromatin Modifying Protein; CHarged Multivesicular body Protein), which is encoded by an alternative open reading frame in the PRSM1 gene and is conserved in both complex and simple eukaryotes. CHMP1 contains a predicted bipartite nuclear localization signal and distributes as distinct forms to the cytoplasm and the nuclear matrix in all cell lines tested. We have constructed a stable HEK293 cell line that inducibly overexpresses CHMP1 under ecdysone control. Overexpressed CHMP1 localizes to a punctate subnuclear pattern, encapsulating regions of nuclease-resistant, condensed chromatin. These novel structures are also frequently surrounded by increased histone H3 phosphorylation and acetylation. CHMP1 can recruit a PcG protein, BMI1, to these regions of condensed chromatin and can cooperate with co-expressed vertebrate Pcl in a Xenopus embryo PcG assay; this is consistent with a role in PcG function. In combination, these observations suggest that CHMP1 plays a role in stable gene silencing within the nucleus.

Evidence for DNA binding activity of numatrin (B23), a cell cycle-regulated nuclear matrix protein

1990 ◽  
Vol 1087 (2) ◽  
pp. 127-136 ◽  
Author(s):  
Nili Feuerstein ◽  
James J. Mond ◽  
Paul R. Kinchington ◽  
Robert Hickey ◽  
Marja-Liisa Karjalainen Lindsberg ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Binding ◽  
Nuclear Matrix ◽  
Matrix Protein ◽  
Binding Activity ◽  
Nuclear Matrix Protein ◽  
Dna Binding Activity ◽  
A Cell

Nuclear matrix protein mitotin messenger RNA is expressed at constant levels during the cell cycle

1991 ◽  
Vol 177 (1) ◽  
pp. 395-400 ◽  
Author(s):  
Ivan T. Todorov ◽  
Jacques Lavigne ◽  
Françoise Sakr ◽  
Radka Kaneva ◽  
Sylvain Foisy ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Nuclear Matrix ◽  
Messenger Rna ◽  
Matrix Protein ◽  
Nuclear Matrix Protein

Synthesis and Phosphorylation of the 125 K Nuclear Matrix Protein Mitotin during the Cell Cycle

1990 ◽  
pp. 323-328
Author(s):  
I. T. Todorov ◽  
N. Z. Zhelev ◽  
R. N. Philipova ◽  
V. Bibor-Hardy ◽  
A. A. Hadjiolov
Keyword(s):  
Cell Cycle ◽  
Nuclear Matrix ◽  
Matrix Protein ◽  
Nuclear Matrix Protein

scholarly journals Different Concentrations of Mg++ Ions Affect Nuclear Matrix Protein Distribution During Thermal Stabilization of Isolated Nuclei

1997 ◽  
Vol 45 (10) ◽  
pp. 1317-1328 ◽  
Author(s):  
Luca M. Neri ◽  
S. Capitani ◽  
Aurelio Valmori ◽  
Beat M. Riederer ◽  
Alberto M. Martelli
Keyword(s):  
Nuclear Matrix ◽  
Matrix Protein ◽  
Thermal Stabilization ◽  
Cell Types ◽  
Nuclear Bodies ◽  
Immunofluorescent Staining ◽  
Protein Distribution ◽  
Nuclear Scaffold ◽  
Isolated Nuclei ◽  
Confocal Scanning Laser Microscope

The nuclear matrix, a proteinaceous network believed to be a scaffolding structure determining higher-order organization of chromatin, is usually prepared from intact nuclei by a series of extraction steps. In most cell types investigated the nuclear matrix does not spontaneously resist these treatments but must be stabilized before the application of extracting agents. Incubation of isolated nuclei at 37C or 42C in buffers containing Mg++ has been widely employed as stabilizing agent. We have previously demonstrated that heat treatment induces changes in the distribution of three nuclear scaffold proteins in nuclei prepared in the absence of Mg++ ions. We studied whether different concentrations of Mg++ (2.0–5 mM) affect the spatial distribution of nuclear matrix proteins in nuclei isolated from K562 erythroleukemia cells and stabilized by heat at either 37C or 42C. Five proteins were studied, two of which were RNA metabolism-related proteins (a 105-kD component of splicing complexes and an RNP component), one a 126-kD constituent of a class of nuclear bodies, and two were components of the inner matrix network. The localization of proteins was determined by immunofluorescent staining and confocal scanning laser microscope. Mg++ induced significant changes of antigen distribution even at the lowest concentration employed, and these modifications were enhanced in parallel with increase in the concentration of the divalent cation. The different sensitivity to heat stabilization and Mg++ of these nuclear proteins might reflect a different degree of association with the nuclear scaffold and can be closely related to their functional or structural role.

scholarly journals Drosophila RB Proteins Repress Differentiation-Specific Genes via Two Different Mechanisms

2010 ◽  
Vol 30 (10) ◽  
pp. 2563-2577 ◽  
Author(s):  
Hangnoh Lee ◽  
Katsuhito Ohno ◽  
Yekaterina Voskoboynik ◽  
Linda Ragusano ◽  
Anna Martinez ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Target Genes ◽  
Polycomb Group ◽  
Promoter Regions ◽  
Proliferating Cells ◽  
Developmentally Regulated ◽  
Independent Manner ◽  
Transcription Start Sites ◽  
Expression Of Genes ◽  
Division Cell

ABSTRACT The RB and E2F proteins play important roles in the regulation of cell division, cell death, and development by controlling the expression of genes involved in these processes. The mechanisms of repression by the retinoblastoma protein (pRB) have been extensively studied at cell cycle-regulated promoters. However, little is known about developmentally regulated E2F/RB genes. Here, we have taken advantage of the simplicity of the E2F/RB pathway in flies to inspect the regulation of differentiation-specific target genes. These genes are repressed by dE2F2/RBF and a recently identified RB-containing complex, dREAM/MMB, in a cell type- and cell cycle-independent manner. Our studies indicate that the mechanism of repression differs from that of cell cycle-regulated genes. We find that two different activities are involved in their regulation and that in proliferating cells, both are required to maintain repression. First, dE2F2/RBF and dREAM/MMB employ histone deacetylase (HDAC) activities at promoter regions. Remarkably, we have also uncovered an unconventional mechanism of repression by the Polycomb group (PcG) protein Enhancer of zeste [E(Z)], which is involved in silencing of these genes through the dimethylation of histone H3 Lys27 at nucleosomes located downstream of the transcription start sites (TSS).

984: Variability in the Performance of Nuclear Matrix Protein 22 in the Detection of Bladder Cancer

2006 ◽  
Vol 175 (4S) ◽  
pp. 317-317
Author(s):  
Shahrokh F. Shariat ◽  
Michael Marberger ◽  
Yair Lotan ◽  
Marta Sanchez-Carbayo ◽  
Craig D. Zippe ◽  
...  
Keyword(s):  
Bladder Cancer ◽  
Nuclear Matrix ◽  
Matrix Protein ◽  
Nuclear Matrix Protein
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