scholarly journals Cętki jądrowe jako modelowe ciałka jądrowe. Cętki jądrowe w układzie nerwowym

Kosmos ◽  
2020 ◽  
Vol 69 (1) ◽  
pp. 17-35
Author(s):  
Andrzej Szczepankiewicz
Keyword(s):  
Nuclear Bodies ◽  
Nuclear Speckles ◽  
Interchromatin Granule Clusters ◽  
Interchromatin Granule

Jądro komórkowe oprócz heterochromatyny czyli kompleksu DNA i białek histonowych, zawiera struktury zwane ciałkami jądrowymi (ang. nuclear bodies). Są to niewielkie, zazwyczaj koliste twory ?zawieszone? w nukleoplazmie, składające się z białek lub białek i niekodującego RNA. Znanych jest kilkanaście rodzajów takich struktur. Artykuł przedstawia obecny stan wiedzy na temat ciałek nazywanych w angielskiej literaturze nuclear speckles, czyli cętki jądrowe lub interchromatin granule clusters czyli skupiska ziaren interchromatynowych. Zaobserwowane po raz pierwszy przez Romana y Cajala w neuronach, obecne jednak we wszystkich typach komórek, struktury te uważane są za magazyny i miejsce modyfikacji czynników składania (splicingu) mRNA. Najnowsze badania, prezentowane w artykule pozwalają sądzić, że ich udział w metabolizmie RNA jest bardziej złożony. Świadczą o tym również doniesienia o roli cętek.

scholarly journals Disassembly of interchromatin granule clusters alters the coordination of transcription and pre-mRNA splicing

2002 ◽  
Vol 156 (3) ◽  
pp. 425-436 ◽  
Author(s):  
Paula Sacco-Bubulya ◽  
David L. Spector
Keyword(s):  
Mammalian Cell ◽  
Protein Interactions ◽  
Sr Proteins ◽  
Mrna Splicing ◽  
Cell Nuclei ◽  
Nuclear Speckles ◽  
Sr Protein ◽  
Interchromatin Granule Clusters ◽  
Interchromatin Granule

To examine the involvement of interchromatin granule clusters (IGCs) in transcription and pre-mRNA splicing in mammalian cell nuclei, the serine-arginine (SR) protein kinase cdc2-like kinase (Clk)/STY was used as a tool to manipulate IGC integrity in vivo. Both immunofluorescence and transmission electron microscopy analyses of cells overexpressing Clk/STY indicate that IGC components are completely redistributed to a diffuse nuclear localization, leaving no residual structure. Conversely, overexpression of a catalytically inactive mutant, Clk/STY(K190R), causes retention of hypophosphorylated SR proteins in nuclear speckles. Our data suggest that the protein–protein interactions responsible for the clustering of interchromatin granules are disrupted when SR proteins are hyperphosphorylated and stabilized when SR proteins are hypophosphorylated. Interestingly, cells without intact IGCs continue to synthesize nascent transcripts. However, both the accumulation of splicing factors at sites of pre-mRNA synthesis as well as pre-mRNA splicing are dramatically reduced, demonstrating that IGC disassembly perturbs coordination between transcription and pre-mRNA splicing in mammalian cell nuclei.

Organization of transcription and pre-mRNA splicing within the mammalian cell nucleus

1995 ◽  
Vol 53 ◽  
pp. 768-769
Author(s):  
D.L. Spector ◽  
S. Huang ◽  
S. Kaurin
Keyword(s):  
Rna Polymerase Ii ◽  
Cell Nucleus ◽  
Functional Organization ◽  
Mrna Splicing ◽  
Splicing Factors ◽  
Interchromatin Granule Clusters ◽  
Interchromatin Granule ◽  
Nuclear Regions ◽  
Relationship Of ◽  
Perichromatin Fibrils

We have been interested in the organization of RNA polymerase II transcription and pre-mRNA splicing within the cell nucleus. Several models have been proposed for the functional organization of RNA within the eukaryotic nucleus and for the relationship of this organization to the distribution of pre-mRNA splicing factors. One model suggests that RNAs which must be spliced are capable of recruiting splicing factors to the sites of transcription from storage and/or reassembly sites. When one examines the organization of splicing factors in the nucleus in comparison to the sites of chromatin it is clear that splicing factors are not localized in coincidence with heterochromatin (Fig. 1). Instead, they are distributed in a speckled pattern which is composed of both perichromatin fibrils and interchromatin granule clusters. The perichromatin fibrils are distributed on the periphery of heterochromatin and on the periphery of interchromatin granule clusters as well as being diffusely distributed throughout the nucleoplasm. These nuclear regions have been previously shown to represent initial sites of incorporation of 3H-uridine.

scholarly journals Whole-genome screening identifies proteins localized to distinct nuclear bodies

2013 ◽  
Vol 203 (1) ◽  
pp. 149-164 ◽  
Author(s):  
Ka-wing Fong ◽  
Yujing Li ◽  
Wenqi Wang ◽  
Wenbin Ma ◽  
Kunpeng Li ◽  
...  
Keyword(s):  
Posttranscriptional Regulation ◽  
Nuclear Bodies ◽  
Cajal Bodies ◽  
Nuclear Speckles ◽  
Genome Wide ◽  
A Genome ◽  
Human Proteins ◽  
Genome Screening ◽  
Interchromatin Space ◽  
Polycomb Bodies

The nucleus is a unique organelle that contains essential genetic materials in chromosome territories. The interchromatin space is composed of nuclear subcompartments, which are defined by several distinctive nuclear bodies believed to be factories of DNA or RNA processing and sites of transcriptional and/or posttranscriptional regulation. In this paper, we performed a genome-wide microscopy-based screening for proteins that form nuclear foci and characterized their localizations using markers of known nuclear bodies. In total, we identified 325 proteins localized to distinct nuclear bodies, including nucleoli (148), promyelocytic leukemia nuclear bodies (38), nuclear speckles (27), paraspeckles (24), Cajal bodies (17), Sam68 nuclear bodies (5), Polycomb bodies (2), and uncharacterized nuclear bodies (64). Functional validation revealed several proteins potentially involved in the assembly of Cajal bodies and paraspeckles. Together, these data establish the first atlas of human proteins in different nuclear bodies and provide key information for research on nuclear bodies.

scholarly journals In vivo analysis of the stability and transport of nuclear poly(A)+ RNA.

1994 ◽  
Vol 126 (4) ◽  
pp. 877-899 ◽  
Author(s):  
S Huang ◽  
T J Deerinck ◽  
M H Ellisman ◽  
D L Spector
Keyword(s):  
Rna Polymerase Ii ◽  
Mammalian Cells ◽  
Stable Population ◽  
Nuclear Pore ◽  
Nuclear Pore Complexes ◽  
Nuclear Pores ◽  
Electron Microscopic ◽  
Interchromatin Granule Clusters ◽  
Interchromatin Granule ◽  
Pore Complexes

We have studied the distribution of poly(A)+ RNA in the mammalian cell nucleus and its transport through nuclear pores by fluorescence and electron microscopic in situ hybridization. Poly(A)+ RNA was detected in the nucleus as a speckled pattern which includes interchromatin granule clusters and perichromatin fibrils. When cells are fractionated by detergent and salt extraction as well as DNase I digestion, the majority of the nuclear poly(A)+ RNA was found to remain associated with the nonchromatin RNP-enriched fraction of the nucleus. After inhibition of RNA polymerase II transcription for 5-10 h, a stable population of poly(A)+ RNA remained in the nucleus and was reorganized into fewer and larger interchromatin granule clusters along with pre-mRNA splicing factors. This stable population of nuclear RNA may play an important role in nuclear function. Furthermore, we have observed that, in actively transcribing cells, the regions of poly(A)+ RNA which reached the nuclear pore complexes appeared as narrow concentrations of RNA suggesting a limited or directed pathway of movement. All of the observed nuclear pores contained poly(A)+ RNA staining suggesting that they are all capable of exporting RNA. In addition, we have directly visualized, for the first time in mammalian cells, the transport of poly(A)+ RNA through the nuclear pore complexes.

scholarly journals p300/CBP-associated Factor Drives DEK into Interchromatin Granule Clusters

2005 ◽  
Vol 280 (36) ◽  
pp. 31760-31767 ◽  
Author(s):  
Joanne Cleary ◽  
Kajal V. Sitwala ◽  
Michael S. Khodadoust ◽  
Roland P. S. Kwok ◽  
Nirit Mor-Vaknin ◽  
...  
Keyword(s):  
Associated Factor ◽  
Interchromatin Granule Clusters ◽  
Interchromatin Granule

Interchromatin granule clusters of the scorpionfly oocytes contain poly(A)+RNA, heterogeneous ribonucleoproteins A/B and mRNA export factor NXF1

2010 ◽  
Vol 34 (12) ◽  
pp. 1163-1170 ◽  
Author(s):  
Florina M Batalova ◽  
Dmitry S Bogolyubov ◽  
Vladimir N Parfenov
Keyword(s):  
Mrna Export ◽  
Interchromatin Granule Clusters ◽  
Interchromatin Granule

scholarly journals Rapid, Diffusional Shuttling of Poly(A) RNA between Nuclear Speckles and the Nucleoplasm

2006 ◽  
Vol 17 (3) ◽  
pp. 1239-1249 ◽  
Author(s):  
Joan C. Ritland Politz ◽  
Richard A. Tuft ◽  
Kannanganattu V. Prasanth ◽  
Nina Baudendistel ◽  
Kevin E. Fogarty ◽  
...  
Keyword(s):  
Fluorescent Protein ◽  
Correlation Spectroscopy ◽  
Nuclear Bodies ◽  
Metabolic Energy ◽  
Splicing Factors ◽  
Nuclear Speckles ◽  
Hybridization Probe ◽  
Fluorescence Correlation ◽  
Discernible Effect ◽  
Rate Of Movement

Speckles are nuclear bodies that contain pre-mRNA splicing factors and polyadenylated RNA. Because nuclear poly(A) RNA consists of both mRNA transcripts and nucleus-restricted RNAs, we tested whether poly(A) RNA in speckles is dynamic or rather an immobile, perhaps structural, component. Fluorescein-labeled oligo(dT) was introduced into HeLa cells stably expressing a red fluorescent protein chimera of the splicing factor SC35 and allowed to hybridize. Fluorescence correlation spectroscopy (FCS) showed that the mobility of the tagged poly(A) RNA was virtually identical in both speckles and at random nucleoplasmic sites. This same result was observed in photoactivation-tracking studies in which caged fluorescein-labeled oligo(dT) was used as hybridization probe, and the rate of movement away from either a speckle or nucleoplasmic site was monitored using digital imaging microscopy after photoactivation. Furthermore, the tagged poly(A) RNA was observed to rapidly distribute throughout the entire nucleoplasm and other speckles, regardless of whether the tracking observations were initiated in a speckle or the nucleoplasm. Finally, in both FCS and photoactivation-tracking studies, a temperature reduction from 37 to 22°C had no discernible effect on the behavior of poly(A) RNA in either speckles or the nucleoplasm, strongly suggesting that its movement in and out of speckles does not require metabolic energy.

scholarly journals An Immunocytochemical Study of Interchromatin Granule Clusters in Early Mouse Embryos

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Irina Bogolyubova ◽  
Dmitry Bogolyubov
Keyword(s):  
Rna Polymerase Ii ◽  
De Novo ◽  
Gene Activation ◽  
Mouse Embryos ◽  
Molecular Composition ◽  
Interchromatin Granule Clusters ◽  
Interchromatin Granule ◽  
Zygotic Gene ◽  
Early Mouse ◽  
Nuclear Domains

Interchromatin granule clusters (IGCs) are universal nuclear domains. Their molecular composition and functions were studied in detail in somatic cells. Here, we studied IGCs in the nuclei of early mouse embryos during zygotic gene activation (ZGA). We found that the size of IGCs gradually increases during realization of ZGA events. Using immunocytochemical approaches, we showed that the molecular composition of IGCs is also modified in mouse embryos. The hyperphosphorylated form of RNA polymerase II and the transcription factor TFIID have been revealed in IGCs before the end of ZGA. Association of these factors with IGCs became more noticeable during ZGA realization. Our data suggest that IGCs in early mouse embryos have some functional peculiarities connected most probably with IGC formationde novo. We believe that IGCs in early mouse embryos not only are storage sites of splicing factors but also may be involved in mRNA metabolism and represent the multifunctional nuclear domains.

scholarly journals Speckles and paraspeckles coordinate to regulate HSV-1 genes transcription

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Kun Li ◽  
Ziqiang Wang
Keyword(s):  
Nuclear Bodies ◽  
Nuclear Speckles ◽  
Core Component ◽  
Herpes Simplex Virus 1 ◽  
The Core ◽  
Viral Genes ◽  
Infected Cells ◽  
Simplex Virus ◽  
Insight Into ◽  
Hsv 1

AbstractNumbers of nuclear speckles and paraspeckles components have been demonstrated to regulate herpes simplex virus 1 (HSV-1) replication. However, how HSV-1 infection affects the two nuclear bodies, and whether this influence facilitates the expression of viral genes, remains elusive. In the current study, we found that HSV-1 infection leads to a redistribution of speckles and paraspeckles components. Serine/arginine-rich splicing factor 2 (SRSF2), the core component of speckles, was associated with multiple paraspeckles components, including nuclear paraspeckles assembly transcript 1 (NEAT1), PSPC1, and P54nrb, in HSV-1 infected cells. This association coordinates the transcription of viral genes by binding to the promoters of these genes. By association with the enhancer of zeste homolog 2 (EZH2) and P300/CBP complex, NEAT1 and SRSF2 influenced the histone modifications located near viral genes. This study elucidates the interplay between speckles and paraspeckles following HSV-1 infection and provides insight into the mechanisms by which HSV-1 utilizes host cellular nuclear bodies to facilitate its life cycle.

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