Nuclear distribution of RNA polymerase II in human oocytes from antral follicles: Dynamics relative to the transcriptional state and association with splicing factors

Parfenov, V. N.; Davis, Donna S.; Kostyuchek, D.; Murti, K.G.

doi:10.1002/(sici)1097-4644(20000615)77:4<654::aid-jcb13>3.0.co;2-4

Cited by 22 publications

(11 citation statements)

References 55 publications

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“…These experiments suggest that the transcriptional silencing in oocytes might be caused by histone deacetylation that causes chromatin condensation and in such case RNA polymerase II might be prevented from reaching its target sequence. In turn, this exclusion of RNA polymerase II might lead to sequestration of this protein complex together with some transcription factors (Sun et al 2007, Parfenov et al 2000. Even though our results speak against this scenario, we have decided to follow the localisation of HDAC1 in mouse GV stage oocytes and in fusion pairs after 3 and 20 h post incubation.…”

Section: Detection Of Rna Polymerase II Levels By Western Blottingmentioning

confidence: 88%

The inability of fully grown germinal vesicle stage oocyte cytoplasm to transcriptionally silence transferred transcribing nuclei

Fulka

Nováková

Mosko

et al. 2009

Histochem Cell Biol

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For somatic cell nuclear transfer cytoplasts from metaphase II, oocytes are exclusively used. However, it is evident that certain reprogramming activities are present in oocytes even at earlier stages of maturation. These activities are, however, only poorly characterised. The main reason for this is that even the intrinsic oocyte processes are insufficiently understood. The mammalian oocyte is a highly specialised cell that harbours many specific characteristics. One of these is its particularly large size when compared to somatic cells. As the oocyte enters the growth phase its volume, as well as the amount of material, increases considerably. Thus, it is clear that the oocyte must possess the machinery to accomplish this incredible material accumulation. When the growth phase is completed, the transcription ceases and the oocyte becomes transcriptionally inactive. In our study, we have used the model system of oocyte fusion (transcribing x non-transcribing germinal vesicle (GV) stage oocytes) as a substitute for a somatic cell nuclear transfer schemes where the somatic cell nucleus would be introduced into a cytoplast obtained from a GV stage oocyte. We wanted to determine if the fully grown GV stage oocyte could induce reprogramming of transcriptionally active transferred nucleus by suppressing this activity. In order to evaluate possible changes in transcriptional properties after nuclear transfer, we also investigated the mechanism of transcriptional silencing taking place when the oocyte reaches its full size as well as the fate of the components namely of the RNA polymerase II (Pol II) transcriptional and splicing machinery. Here, we show that while the Pol II is degraded in fully grown GV stage oocytes and the splicing proteins undergo significant rearrangement, these oocytes are unable to induce similar changes in transcriptionally active nuclei even after a prolonged culture interval.

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Section: Detection Of Rna Polymerase II Levels By Western Blottingmentioning

confidence: 88%

The inability of fully grown germinal vesicle stage oocyte cytoplasm to transcriptionally silence transferred transcribing nuclei

Fulka

Nováková

Mosko

et al. 2009

Histochem Cell Biol

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“…The mechanism involved in coordinating changes in large-scale chromatin structure with the onset of transcriptional silencing in mammalian oocytes are poorly understood (De La Fuente et al, 2004a;De La Fuente, 2006), but several experimental evidences indicate that unique strategies, which are most likely part of a complex physiological process, are set in place for the control of global transcription in oocytes. Although the specific role of some putative regulatory factors and the involvement of epigenetic modifications have been considered, (Worrad et al, 1994;Bellier et al, 1997;Gebara et al, 1997;Parfenov et al, 2000;Zatsepina et al, 2000;Fair et al, 2001;Burns et al, 2003;Miyara et al, 2003;Parfenov et al, 2003;Baran et al, 2004;Bjerregaard et al, 2004;De La Fuente et al, 2004a,b;reviewed in De La Fuente, 2006), the principal mechanism(s) responsible for silencing the oocyte genome remain to be determined.…”

Section: Discussionmentioning

confidence: 99%

Oocyte morphology and transcriptional silencing in relation to chromatin remodeling during the final phases of bovine oocyte growth

Lodde

Modina

Maddox-Hyttel

et al. 2007

Molecular Reproduction Devel

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The complexity of the events which orchestrate mammalian oocyte growth and ultimate acquisition of developmental competence is still unclear and under continuous investigation. Starting from the observation that germinal vesicle (GV) bovine oocytes exhibit different patterns of chromatin configuration (from GV0 to GV3), the present study aimed at analyzing the morphology of the nuclear and the cytoplasmic compartments and to determine the total transcriptional activity of immature oocytes sorted on the basis of their chromatin configuration. The oocyte morphology was analyzed by light microscopy (LM) on semi-thin sections and transmission electron microscopy, and the global transcriptional activity was analyzed by H(3)-Uridine incorporation and subsequent autoradiography on semi-thin sections. LM confirmed the increase in chromatin condensation from GV0 to GV3. Ultrastructurally, the nucleolus was fibrillo granular at GV0 while the other stages displayed an electron-dense fibrillar sphere with the remnant of a fibrillar center on the surface. Organelles were dispersed in the cytoplasm at GV0 while at GV1 and GV2 most of them were homogenously distributed in the oocyte cortex. At GV3 most organelles were found in clusters in the oocyte cortex. Typical features of completion of the oocyte growth phase, like undulation of the nuclear envelope and reduction of the size of Golgi complex were found at GV2 and GV3. Moreover, GV3 oocytes presented cortical granules that displayed varying degrees of degeneration. Autoradiographic labeling showed that oocytes with GV0 configuration exhibited high level of RNA synthesis, GV1 and GV2 stages showed a remarkable decrease of transcription, and the acquisition of GV3 configuration was associated with global repression of transcriptional activity. Our findings suggest a temporal relationship between the chromatin remodeling process and the main morpho-functional events that characterize the final growth phase in bovine oocyte.

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“…It is likely that the list of CFs being displaced during meiosis extends far beyond those examined so far. In addition, changes in chemical modifications and functional status of critical transcription factors [5,[24][25][26][27] could prompt disassembly of the transcription apparatus. When contacts between chromatin and a broad range of critical transcription factors and regulatory factors are disrupted, transcription cannot occur.…”

Section: Discussionmentioning

confidence: 99%

“…In addition, it was found that the component of the RNA polymerase II holoenzyme is dephosphorylated and translocated away from active sites [5,[24][25][26][27], and members of the polycomb group proteins (Ring1B and Rae28/Ph1) are dissociated from meiotic chromatin in GV oocytes [28]. Although it is conceived that these events could cause a deficient transcription in fully grown oocytes [5,23,25,26], the scope and the data of the investigations were too limited to provide a sufficient explanation for the genome-wide transcription inactivation.…”

Section: Introductionmentioning

confidence: 99%

Nuclear reprogramming: the zygotic transcription program is established through an “erase-and-rebuild” strategy

Sun

Fang

et al. 2007

Cell Res

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npgOocytes display a maternal-specific gene expression profile, which is switched to a zygotic profile when a haploid set of chromatin is passed on to the fertilized egg that develops into an embryo. The mechanism underlying this transcription reprogramming is currently unknown. Here we demonstrate that by the time when transcription is shut down in germinal vesicle oocytes, a range of general transcription factors and transcriptional regulators are dissociated from the chromatin. The global dissociation of chromatin factors (CFs) disrupts physical contacts between the chromatin and CFs and leads to erasure of the maternal transcription program at the functional level. Critical transcription factors and regulators remain separated from chromatin for a prolonged period, and become re-associated with chromatin shortly after pronuclear formation. This is followed temporally by the re-establishment of nuclear functions such as DNA replication and transcription. We propose that the maternal transcription program is erased during oogenesis to generate a relatively naïve chromatin and the zygotic transcription program is rebuilt de novo after fertilization. This process is termed as the "erase-and-rebuild" process, which is used to reset the transcription program, and most likely other nuclear processes as well, from a maternal one to that of the embryo. We further show in the accompanying paper (Gao T, et al., Cell Res 2007; 17:135-150.) that the same strategy is also employed to reprogram transcriptional profiles in somatic cell nuclear transfer and parthenogenesis, suggesting that this model is universally applicable to all forms of transcriptional reprogramming during early embryogenesis. Displacement of CFs from chromatin also offers an explanation for the phenomenon of transcription silence during the maternal to zygotic transition.

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Nuclear distribution of RNA polymerase II in human oocytes from antral follicles: Dynamics relative to the transcriptional state and association with splicing factors

Cited by 22 publications

References 55 publications

The inability of fully grown germinal vesicle stage oocyte cytoplasm to transcriptionally silence transferred transcribing nuclei

The inability of fully grown germinal vesicle stage oocyte cytoplasm to transcriptionally silence transferred transcribing nuclei

Oocyte morphology and transcriptional silencing in relation to chromatin remodeling during the final phases of bovine oocyte growth

Nuclear reprogramming: the zygotic transcription program is established through an “erase-and-rebuild” strategy

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