The karyosphere capsule in oocytes of hibernating frogs Rana temporaria contains actin, lamins, and SnRNP

Ilicheva, Nadya V; Kiryushina, D. Y.; Baskakov, A. V.; Podgornaya, O. I.

doi:10.1134/s1990519x16050059

Cited by 5 publications

(5 citation statements)

References 38 publications

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“…As shown in Figure , pseudomembrane localization also changes following the CytD treatment. Apart from actin, lamins were also shown to be structural components of the KC . Lamins form polymers that compose a network of filaments underlying the nuclear membrane; thus, they potentially could support structures within the KC in the absence of actin filaments.…”

Section: Discussionmentioning

confidence: 99%

“…We propose that the difference in staining by ABs to C‐ and N‐actin ends reflects the difference between conventional actin forms and actin stored in chromatin remodeling complexes. The appearance of remodeling complexes storing patches in frog oocyte nuclei differs from that of nuclear speckles, and is reminiscent of small RNP containing particles.…”

Section: Discussionmentioning

confidence: 99%

“…Apart from actin, lamins were also shown to be structural components of the KC. 45 Lamins form polymers that compose a network of filaments underlying the nuclear membrane; thus, they potentially could support structures within the KC in the absence of actin filaments. Our experiments on actin depolymerization elicit that polymeric actins-rather than lamins-are key structural components responsible for KC integrity.…”

Section: Nuclear Actinmentioning

confidence: 99%

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Actin depolymerization disrupts karyosphere capsule integrity but not residual transcription in late oocytes of the grass frog Rana temporaria

Ilicheva

Podgornaya

2019

J of Cellular Biochemistry

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Late diplotene oocytes are characterized by an essential decrease in transcriptional activity. At this time, chromosomes condense and form a compact structure named a karyosphere. The karyosphere of grass frogs Rana temporaria is surrounded by a fibrillar karyosphere capsule (KC). One of the main protein constituents of R. temporaria KC is actin. In this study, we used antibodies against different actin epitopes to trace different forms of actin in the KC. We also investigated the effect of F‐actin depolymerization on the oocyte nuclear structures and transcription of chromatin DNA and rDNA in the amplified nucleoli. It was determined that disruption of actin filaments leads to chromosome shrinkage, nucleoli fusion, and distortion of the KC structure, but does not inhibit residual transcription in both the karyosphere and the nucleoli.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Nuclear Actinmentioning

confidence: 99%

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Actin depolymerization disrupts karyosphere capsule integrity but not residual transcription in late oocytes of the grass frog Rana temporaria

Ilicheva

Podgornaya

2019

J of Cellular Biochemistry

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“…In particular, snRNAs revealed in the KC of these species carry the 2,2,7-trimethylguanosine (TMG) cap, characteristic of the 5′ end of many splicing snRNAs that have already completed the cytoplasmic period of their processing [ 49 ]. Interestingly, the “Sm-epitope” of snRNPs was detected recently in the KC of frog oocytes [ 50 ] (Ilicheva et al, 2016). Even in the species without a well-developed fibrous capsule (e.g., Tenebrio molitor or Panorpa communis ), oocyte chromosomes are tightly associated with a fibrogranular material containing snRNPs and other RNA transcription and processing factors [ 51 – 53 ].…”

Section: Discussionmentioning

confidence: 99%

The exon junction complex factor Y14 is dynamic in the nucleus of the beetle Tribolium castaneum during late oogenesis

et al. 2017

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BackgroundThe oocyte chromosomes of the red flour beetle, Tribolium castaneum, are gathered into a knot, forming a karyosphere at the diplotene stage of meiotic prophase. Chromatin rearrangement, which is a characteristic feature of oocyte maturation, is well documented. The T. castaneum karyosphere is surrounded by a complex extrachromosomal structure termed the karyosphere capsule. The capsule contains the vast majority of oocyte RNA. We have previously shown using a BrUTP assay that oocyte chromosomes in T. castaneum maintain residual transcription up to the very end of oocyte maturation. Karyosphere transcription requires evidently not only transcription factors but also mRNA processing factors, including the components of the exon junction complex with its core component, the splicing factor Y14. We employed a gene engineering approach with injection of mRNA derived from the Myc-tagged Y14 plasmid-based construct in order to monitor the newly synthesized fusion protein in the oocyte nuclei.ResultsOur preliminary data have been presented as a brief correspondence elsewhere. Here, we provide a full-length article including immunoelectron-microscopy localization data on Y14–Myc distribution in the nucleus of previtellogenic and vitellogenic oocytes. The injections of the fusion protein Y14–Myc mRNA into the oocytes showed a dynamic pattern of the protein distribution. At the previtellogenic stage, there are two main locations for the protein: SC35 domains (the analogues of interchromatin granule clusters or nuclear speckles) and the karyosphere capsule. At the vitellogenic stage, SC35 domains were devoid of labels, and Y14–Myc was found in the perichromatin region of the karyosphere, presumably at the places of residual transcription. We show that karyosphere formation is accompanied by the movement of a nuclear protein while the residual transcription occurs during genome inactivation.ConclusionsOur data indicate that the karyosphere capsule, being a destination site for a protein involved in mRNA splicing and export, is not only a specializes part of nuclear matrix separating the karyosphere from the products of chromosome activity, as believed previously, but represents a special nuclear compartment involved in the processes of gene expression in the case the karyosphere retains residual transcription activity.Electronic supplementary materialThe online version of this article (10.1186/s13039-017-0342-4) contains supplementary material, which is available to authorized users.

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“…The two components isolated during NM preparation are the internal NM and the nuclear lamina (NL) [ 8 ]. The internal NM can be observed in vivo during oogenesis, where it supports the chromosomes in large germinal vesicles of the oocyte [ 9 , 10 , 11 , 12 , 13 , 14 , 15 ], but its presence in ordinary somatic cells is questionable [ 16 , 17 ]. NL, which lies beneath the inner nuclear membrane, is a relatively insoluble fibrous structure [ 18 ].…”

Section: Introductionmentioning

confidence: 99%

The Long Linker Region of Telomere-Binding Protein TRF2 Is Responsible for Interactions with Lamins

Travina

Ilicheva

Mittenberg

et al. 2021

IJMS

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Telomere-binding factor 2 (TRF2) is part of the shelterin protein complex found at chromosome ends. Lamin A/C interacts with TRF2 and influences telomere position. TRF2 has an intrinsically disordered region between the ordered dimerization and DNA-binding domains. This domain is referred to as the long linker region of TRF2, or udTRF2. We suggest that udTRF2 might be involved in the interaction between TRF2 and lamins. The recombinant protein corresponding to the udTRF2 region along with polyclonal antibodies against this region were used in co-immunoprecipitation with purified lamina and nuclear extracts. Co-immunoprecipitation followed by Western blots and mass spectrometry indicated that udTRF2 interacts with lamins, preferably lamins A/C. The interaction did not involve any lamin-associated proteins, was not dependent on the post-translation modification of lamins, nor did it require their higher-order assembly. Besides lamins, a number of other udTRF2-interacting proteins were identified by mass spectrometry, including several heterogeneous nuclear ribonucleoproteins (hnRNP A2/B1, hnRNPA1, hnRNP A3, hnRNP K, hnRNP L, hnRNP M), splicing factors (SFPQ, NONO, SRSF1, and others), helicases (DDX5, DHX9, and Eif4a3l1), topoisomerase I, and heat shock protein 71, amongst others. Some of the identified interactors are known to be involved in telomere biology; the roles of the others remain to be investigated. Thus, the long linker region of TRF2 (udTRF2) is a regulatory domain responsible for the association between TRF2 and lamins and is involved in interactions with other proteins.

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The karyosphere capsule in oocytes of hibernating frogs Rana temporaria contains actin, lamins, and SnRNP

Cited by 5 publications

References 38 publications

Actin depolymerization disrupts karyosphere capsule integrity but not residual transcription in late oocytes of the grass frog Rana temporaria

Actin depolymerization disrupts karyosphere capsule integrity but not residual transcription in late oocytes of the grass frog Rana temporaria

The exon junction complex factor Y14 is dynamic in the nucleus of the beetle Tribolium castaneum during late oogenesis

The Long Linker Region of Telomere-Binding Protein TRF2 Is Responsible for Interactions with Lamins

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