scholarly journals rDNA nascent transcripts promote a unique spatial organization during mouse early development

2021 ◽  
Author(s):  
Martine Chebrout ◽  
Maimouna Coura Kone ◽  
Habib U. Jan ◽  
Marie Cournut ◽  
Martine Letheule ◽  
...  
Keyword(s):  
Early Development ◽  
Spatial Organization ◽  
Ribosomal Genes ◽  
Cell Stage ◽  
Major Satellite ◽  
Cell Cycles ◽  
Embryonic Genome ◽  
Active Transcription ◽  
Polymerase I ◽  
Nascent Transcripts

AbstractDuring the first cell cycles of the early development, the chromatin of the embryo is highly reprogrammed alongside that embryonic genome starts its own transcription. The spatial organization of the genome is a major process that contributes to regulating gene transcription in time and space, however, it is poorly studied in the context of early embryos. To study the cause and effect link between transcription and spatial organization in embryos, we focused on the ribosomal genes, that are first silent and begin to transcribe during the 2-cell stage in mouse. We demonstrated that ribosomal sequences are spatially organized in a very peculiar manner from the 2-cell to the 16-cell stage with transcription and processing of ribosomal RNAs excluding mutually. Using drugs inhibiting the RNA polymerase I, we show that this organization, totally different from somatic cells, depends on an active transcription of ribosomal genes and induces a unique chromatin environment that favors major satellite sequences transcription after the 4-cell stage.

Synthesis and phosphorylation of uvomorulin during mouse early development

Development ◽  
1992 ◽  
Vol 115 (1) ◽  
pp. 313-318 ◽  
Author(s):  
M. Sefton ◽  
M.H. Johnson ◽  
L. Clayton
Keyword(s):  
Cell Adhesion ◽  
Early Development ◽  
Adhesion Molecule ◽  
Cell Adhesion Molecule ◽  
Blastocyst Stage ◽  
Embryonic Stage ◽  
Cell Stage ◽  
Mouse Oocytes ◽  
Maternal Mrna ◽  
Embryonic Genome

The cell adhesion molecule, uvomorulin, is synthesised in both the 135 × 10(3) M(r) precursor and 120 × 10(3) M(r) mature forms on maternal mRNA templates in unfertilized and newly fertilized mouse oocytes. Synthesis on maternal message ceases during the 2-cell stage to resume later on mRNA encoded presumptively by the embryonic genome. Uvomorulin is detectable by immunoblotting at all stages upto the blastocyst stage, but shows variations in its total amount and processing with embryonic stage. Whilst only trace levels of phosphorylated uvomorulin are detectable in early and late 4-cell embryos, uvomorulin in 8-cell embryos is phosphorylated.

scholarly journals The regulation of the expression and activation of the essential ATF1 transcription factor in the mouse preimplantation embryo

Reproduction ◽  
2014 ◽  
Vol 148 (2) ◽  
pp. 147-157 ◽  
Author(s):  
X L Jin ◽  
C O'Neill
Keyword(s):  
Transcription Factor ◽  
Transcription Factors ◽  
Map Kinase ◽  
P38 Map Kinase ◽  
Preimplantation Embryos ◽  
Cell Stage ◽  
Calcium Calmodulin Dependent ◽  
Embryonic Genome ◽  
Cell Embryo ◽  
Active Transcription

The co-expression of the CREB and ATF1 transcription factors is required for the development of preimplantation embryos. Embryotropin-mediated, calcium/calmodulin-dependent signalling activates CREB-induced transcription in the two-cell embryo, but the regulation of ATF1 in the embryo is not known. This study demonstrates that ATF1 begins to accumulate within both pronuclei of the mouse zygote by 20 h post-human chorionic gonadotrophin. This did not require new transcription (not blocked by α-amanitin), but was dependent upon protein synthesis (blocked by puromycin) and the activity of P38 MAP kinase. ATF1 becomes an active transcription factor upon being phosphorylated. A marked accumulation of phosphorylated ATF1 was evident in two-cell embryos and this persisted in subsequent stages of development. This phosphorylation was enhanced by the actions of autocrine embryotropic mediators (including Paf) and required the mutual actions of P38 MAP kinase and calmodulin-dependent pathways for maximum levels of phosphorylation. The combined inhibition of these two pathways blocked embryonic genome activation (EGA) and caused embryos to enter a developmental block at the two-cell stage. The members of the CREB family of transcription factors can generate one of the most diverse transcriptomes of any transcription factor. The demonstration of the presence of activated CREB and ATF1 within the embryonic nucleus at the time of EGA places these transcription factors as priority targets as key regulators of EGA.

Maternally inherited rRNA triggers de novo nucleolus formation in porcine embryos

Zygote ◽  
2018 ◽  
Vol 26 (5) ◽  
pp. 395-402
Author(s):  
Martin Morovic ◽  
Olga Østrup ◽  
Frantisek Strejcek ◽  
Michal Benc ◽  
Matej Murin ◽  
...  
Keyword(s):  
De Novo ◽  
Control Group ◽  
Cell Stage ◽  
Transcriptional Inhibition ◽  
Nucleolar Proteins ◽  
Transmission Electron ◽  
Embryonic Genome ◽  
Polymerase I ◽  
Genome Activation

SummaryThe present study examines the role of RNA polymerase I (RPI)-mediated transcription, maternally inherited rRNA and nucleolar proteins in the resumption of fibrillogranular nucleoli during embryonic genome activation (EGA) in porcine embryos. Late 4-cell embryos were incubated in the absence (control) or presence of actinomycin D (AD) (0.2 μg/ml for inhibition of RPI; 2.0 μg/ml for inhibition of total transcription) and late 2-cell embryos were cultured to the late 4-cell stage with 0.2 μg/ml AD to block EGA. Embryos were then processed for reverse-transcriptase polymerase chain reaction (RT-PCR), and for autoradiography (ARG), transmission electron microscopy (TEM), fluorescence in situ hybridization (FISH), silver staining and immunofluorescence (for RPI). Embryos in the control group displayed extranucleolar and intranucleolar ARG labelling, and exhibited de novo synthesis of rRNA and reticulated functional nucleoli. Nucleolar proteins were located in large foci. After RPI inhibition, nucleolar precursors transformed into segregated fibrillogranular structures, however no fibrillar centres were observed. The localization of rDNA and clusters of rRNA were detected in 57.1% immunoprecipitated (IP) analyzed nucleoli and dispersed RPI; 30.5% of nuclei showed large deposits of nucleolar proteins. Embryos from the AD-2.0 group did not display any transcriptional activity. Nucleolar formation was completely blocked, however 39.4% of nuclei showed rRNA clusters; 85.7% of nuclei were co-localized with nucleolar proteins. Long-term transcriptional inhibition resulted in the lack of ARG and RPI labelling; 40% of analyzed nuclei displayed the accumulation of rRNA molecules into large foci. In conclusion, maternally inherited rRNA co-localized with rDNA and nucleolar proteins can initiate a partial nucleolar assembly, resulting in the formation of fibrilogranular structures independently on activation of RPI-mediated transcription.

scholarly journals Direct Interactions with Nascent Transcripts Is Potentially a Common Targeting Mechanism of Long Non-Coding RNAs

Genes ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1483
Author(s):  
Ivan Antonov ◽  
Yulia Medvedeva
Keyword(s):  
Target Genes ◽  
Regulation Of Gene Expression ◽  
Pilot Project ◽  
Base Pairing ◽  
Nascent Transcript ◽  
Active Transcription ◽  
Wet Lab ◽  
In Trans ◽  
Non Coding Rnas ◽  
Nascent Transcripts

Although thousands of mammalian long non-coding RNAs (lncRNAs) have been reported in the last decade, their functional annotation remains limited. A wet-lab approach to detect functions of a novel lncRNA usually includes its knockdown followed by RNA sequencing and identification of the deferentially expressed genes. However, identification of the molecular mechanism(s) used by the lncRNA to regulate its targets frequently becomes a challenge. Previously, we developed the ASSA algorithm that detects statistically significant inter-molecular RNA-RNA interactions. Here we designed a workflow that uses ASSA predictions to estimate the ability of an lncRNA to function via direct base pairing with the target transcripts (co- or post-transcriptionally). The workflow was applied to 300+ lncRNA knockdown experiments from the FANTOM6 pilot project producing statistically significant predictions for 71 unique lncRNAs (104 knockdowns). Surprisingly, the majority of these lncRNAs were likely to function co-transcriptionally, i.e., hybridize with the nascent transcripts of the target genes. Moreover, a number of the obtained predictions were supported by independent iMARGI experimental data on co-localization of lncRNA and chromatin. We detected an evolutionarily conserved lncRNA CHASERR (AC013394.2 or LINC01578) that could regulate target genes co-transcriptionally via interaction with a nascent transcript by directing CHD2 helicase. The obtained results suggested that this nuclear lncRNA may be able to activate expression of the target genes in trans by base-pairing with the nascent transcripts and directing the CHD2 helicase to the regulated promoters leading to open the chromatin and active transcription. Our study highlights the possible importance of base-pairing between nuclear lncRNAs and nascent transcripts for the regulation of gene expression.

scholarly journals Cellular macromolecules-tethered DNA walking indexing to explore nanoenvironments of chromatin modifications

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Feng Chen ◽  
Min Bai ◽  
Xiaowen Cao ◽  
Jing Xue ◽  
Yue Zhao ◽  
...  
Keyword(s):  
Fluorescence Imaging ◽  
Spatial Organization ◽  
High Throughput Sequencing ◽  
Dna Amplification ◽  
Chromatin Modifications ◽  
Dynamic Changes ◽  
Recognition Mechanism ◽  
Cell Cycles ◽  
Dna Modifications ◽  
Relationship Of

AbstractExploring spatial organization and relationship of diverse biomolecules within cellular nanoenvironments is important to elucidate the fundamental processes of life. However, it remains methodologically challenging. Herein, we report a molecular recognition mechanism cellular macromolecules-tethered DNA walking indexing (Cell-TALKING) to probe the nanoenvironments containing diverse chromatin modifications. As an example, we characterize the nanoenvironments of three DNA modifications around one histone posttranslational modification (PTM). These DNA modifications in fixed cells are labeled with respective DNA barcoding probes, and then the PTM site is tethered with a DNA walking probe. Cell-TALKING can continuously produce cleavage records of any barcoding probes nearby the walking probe. New 3’-OH ends are generated on the cleaved barcoding probes to induce DNA amplification for downstream detections. Combining fluorescence imaging, we identify various combinatorial chromatin modifications and investigate their dynamic changes during cell cycles. We also explore the nanoenvironments in different cancer cell lines and clinical specimens. In principle, using high-throughput sequencing instead of fluorescence imaging may allow the detection of complex cellular nanoenvironments containing tens of biomolecules such as transcription factors.

Expression of the HSP 70.1 gene, a landmark of early zygotic activity in the mouse embryo, is restricted to the first burst of transcription

Development ◽  
1995 ◽  
Vol 121 (1) ◽  
pp. 113-122 ◽  
Author(s):  
E. Christians ◽  
E. Campion ◽  
E.M. Thompson ◽  
J.P. Renard
Keyword(s):  
Dna Replication ◽  
Mouse Embryo ◽  
Culture Conditions ◽  
Hsp 70 ◽  
Cell Stage ◽  
Embryonic Genome ◽  
Genome Activation ◽  
Alpha Amanitin ◽  
Zygotic Genome

Activation of the mouse embryonic genome at the 2-cell stage is characterized by the synthesis of several alpha-amanitin-sensitive polypeptides, some of which belong to the multigenic hsp 70 family. In the present work we show that a member of this family, the HSP 70.1 gene, is highly transcribed at the onset of zygotic genome activation. Transcription of this gene began as early as the 1-cell stage. Expression of the gene continued through the early 2-cell stage but was repressed before the completion of the second round of DNA replication. During this period we observed that the level of transcription was modulated by in vitro culture conditions. The coincidence of repression of HSP70.1 transcription with the second round of DNA replication was not found for other transcription-dependent polypeptides synthesized at the 2-cell stage.

Cell division and cell allocation in early mouse development

Development ◽  
1978 ◽  
Vol 48 (1) ◽  
pp. 37-51
Author(s):  
S. J. Kelly ◽  
J. G. Mulnard ◽  
C. F. Graham
Keyword(s):  
Cell Division ◽  
Tritiated Thymidine ◽  
Mouse Embryos ◽  
Mouse Development ◽  
Stages Of Development ◽  
Cell Stage ◽  
Cell Cycles ◽  
Short Cell ◽  
Early Mouse

Cell division was observed in intact and dissociated mouse embryos between the 2-cell stage and the blastocyst in embryos developing in culture. Division to the 4-cell stage was usually asynchronous. The first cell to divide to the 4-cell stage produced descendants which tended to divide ahead of those cells produced by its slow partner at all subsequent stages of development up to the blastocyte stage. The descendants of the first cell to divide to the 4-cell stage did not subsequently have short cell cycles. The first cell or last cell to divide from the 4-cell stage was labelled with tritiated thymidine. The embryo was reassembled, and it was found that the first pair of cells to reach the 8-cell stage contributed disproportionately more descendants to the ICM when compared with the last cell to divide to the 8-cell stage.

The early development of haploid and aneuploid parthenogenetic embryos

Development ◽  
1975 ◽  
Vol 34 (3) ◽  
pp. 645-655
Author(s):  
Matthew H. Kaufman ◽  
Leo Sachs
Keyword(s):  
Early Development ◽  
Polar Body ◽  
Chromosome Counts ◽  
Cell Stage ◽  
Haploid Chromosome Number ◽  
Stage Of Development ◽  
Morula Stage ◽  
Second Polar Body ◽  
Similar Development ◽  
Parthenogenetic Embryos

The early development of parthenogenetically activated oocytes has been studied in C57BL × CBA-T6T6 (F1T6) translocation heterozygote mice and C57BL × CBA-LAC (F1LAC) mice. All F1T6 oocytes had either a quadrivalent or a univalent-trivalent configuration at meiosis I; no such chromosome configurations were observed in the F1LAC oocytes. At ovulation 36·5 % of the F1T6 oocytes had 19 or 21 chromosomes, whereas 97 % of the F1LAC had the normal haploid chromosome number of 20. After parthenogenetic activation, chromosome counts at metaphase of the first cleavage mitosis were made of the eggs with a single pronucleus following extrusion of the second polar body. These activated eggs had similar frequencies of 19, 20 and 21 chromosomes as had the oocytes at ovulation. The activated 1-cell eggs were transferred to the oviducts of pseudopregnant recipients and the embryos recovered 3 days later. At this stage of development, most of the F1T6 embryos with 19 chromosomes were no longer found, but the frequency of 21-chromosome embryos was similar to the frequency of 21-chromosome oocytes and activated eggs. There was a similar mean number of cells in the embryos with 20 and 21 chromosomes. The results indicate that nearly all the embryos with 19 chromosomes failed to develop, probably beyond the 2-cell stage, whereas oocytes with 21 chromosomes had a similar development to oocytes with 20 chromosomes up to the morula stage.

scholarly journals Human embryonic genome activation initiates at the one-cell stage

2021 ◽  
Author(s):  
Maki Asami ◽  
Brian Y.H. Lam ◽  
Marcella K. Ma ◽  
Kara Rainbow ◽  
Stefanie Braun ◽  
...  
Keyword(s):  
Cell Stage ◽  
Embryonic Genome Activation ◽  
Embryonic Genome ◽  
The One ◽  
Genome Activation

scholarly journals IGF-2 receptors are first expressed at the 2-cell stage of mouse development

Development ◽  
1991 ◽  
Vol 111 (4) ◽  
pp. 1057-1060
Author(s):  
M.B. Harvey ◽  
P.L. Kaye
Keyword(s):  
Preimplantation Development ◽  
Mouse Development ◽  
Cell Stage ◽  
Receptor Mrna ◽  
Embryonic Genome

A specific IGF-2 receptor antiserum was used to reveal the presence of IGF-2 receptors during preimplantation development of mice. Receptors were present on 2-, 4- and 8-cell embryos, morulae, blastocysts, and on ICMs isolated prior to staining. There was no evidence for receptors on fertilized eggs. These observations confirm reports of the expression of IGF-2 receptor mRNA as early as the 2-cell stage and refine similar observations in blastocysts to confirm expression in both the TE and ICM. A potential auto/paracrine loop is thus one of the first products of activation of the embryonic genome and is expressed constitutively through preimplantation development.

Sign in / Sign up

Export Citation Format

Share Document