Cajal bodies in insects. II. Molecular composition of cajal bodies in oocytes of house cricket. Relationship between cajal bodies and interchromatin granule clusters

2007 ◽  
Vol 1 (1) ◽  
pp. 14-29 ◽  
Author(s):  
I. S. Stepanova ◽  
D. S. Bogolyubov ◽  
V. N. Parfenov
2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Irina Bogolyubova ◽  
Dmitry Bogolyubov

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.


Author(s):  
D.L. Spector ◽  
S. Huang ◽  
S. Kaurin

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.


1994 ◽  
Vol 126 (4) ◽  
pp. 877-899 ◽  
Author(s):  
S Huang ◽  
T J Deerinck ◽  
M H Ellisman ◽  
D L Spector

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.


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

Kosmos ◽  
2020 ◽  
Vol 69 (1) ◽  
pp. 17-35
Author(s):  
Andrzej Szczepankiewicz

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.


Author(s):  
S. Huang ◽  
T. J. Deerinck ◽  
M. H. Ellisman ◽  
D. L. Spector

Previous studies from our laboratory as well as other laboratories have shown that a variety of pre-mRNA splicing factors are localized to a subnuclear speckled domain when mammalian cells are immunolabeled with antibodies against these pre-mRNA splicing factors. At the electron microscopic level the speckled pattern is composed of both interchromatin granule clusters and perichromatin fibrils. A large body of evidence has accumulated from both our laboratory and other laboratories which has suggested that the perichromatin fibrils represent nascent transcripts and the interchromatin granule clusters represent storage and/or assembly sites for pre-mRNA splicing factors. The majority of substrates for these splicing factors are pre-mRNAs which contain a poly(A) tail of approximately 200-300 nucleotides. During the past year 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 we have found to totally colocalize with pre-mRNA splicing factors at interchromatin granule clusters and perichromatin fibrils.


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