Onset of RNA synthesis and poly (A) content of early rabbit embryos. Comparison with sheep

Kaňka, Jiří; Je, Fléchon; Šutovský, Peter

doi:10.1051/rnd:19930507

Cited by 14 publications

(6 citation statements)

References 11 publications

(14 reference statements)

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“…These parameters are closely related to the transition from maternal to embryonic genome control, which occurs in bovine embryos at the 8-cell stage (Kopečný et al, 1985;Camous et al, 1986;King et al, 1988). In the sheep embryo the major genome activation occurs at the same cleavage stage and is associated with similar structural changes and synthetic activities (Calarco and McLaren, 1976;Kaň ka et al, 1993). In bovine embryos analyzed in our experiments, the onset of RNA synthesis, the ultrastructure of nucleoli, and the degree of chromatin condensation were comparable with those described for normal embryos of this species (Kopečný et al, 1989b;Kopečný and Niemann, 1993;Pavlok et al, 1993).…”

Section: Discussionmentioning

confidence: 99%

Developmental failure of hybrid embryos originated after fertilization of bovine oocytes with ram spermatozoa

1997

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The developmental ability of hybrid zygotes, produced by in vitro fertilization of in vitro matured bovine oocytes with ram sperm, was evaluated by gross morphology, autoradiographic detection of (5‐3H) uridine incorporation, and fine structure morphology. Fertilization was successful in 83% of bovine oocytes inseminated with bull sperm (control embryos) compared with 67% of bovine oocytes inseminated with ram sperm (hybrid embryos) and in both cases appeared two regularly developed pronuclei. Two‐cell embryos were transferred to ewe oviducts and allowed to develop to the 8‐cell stage. Although the ability of hybrid embryos to reach 8‐cell stage was similar to that of control embryos, in nuclei of hybrid embryos the transition from maternal to embryonic genome control assessed according to the onset of RNA synthesis indicated the differences in the frequency of labelled nuclei and intensity of their labelling. In hybrid embryos these parameters were remarkably lower and may reflect the developmental failure of hybrid embryos. These observations are consistent with delay or inefficient reactivation of the embryonic genome in the hybrid embryos. Mol. Reprod. Dev. 48:344–349, 1997. © 1997 Wiley‐Liss, Inc.

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Section: Discussionmentioning

confidence: 99%

Developmental failure of hybrid embryos originated after fertilization of bovine oocytes with ram spermatozoa

1997

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“…Surprisingly, acH3K9/14 signals of in vivo fertilized rabbit embryos were enhanced at the 4-cell stage but not at the 8-cell stage at which the rabbit embryonic genome activation occurs (Kanka et al 1996, Henrion et al 2000, Brunet-Simon et al 2001. However, initiation of mRNA synthesis determined by in situ hybridization with a poly (U) probe was first detectable at the late 2-cell stage (Kanka et al 1993) and autoradiographically detectable initiation of transcription from an embryonic rabbit genome occurs at the 4-cell stage (Christians et al 1994). An intense transcription then starts after the 8-cell stage and includes the onset of rRNA transcription (Kanka et al 1996).…”

Section: In Vitro Developmentmentioning

confidence: 94%

Rabbit somatic cell cloning: effects of donor cell type, histone acetylation status and chimeric embryo complementation

Yang

Hao²,

Keßler³

et al. 2007

Reproduction

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The epigenetic status of a donor nucleus has an important effect on the developmental potential of embryos produced by somatic cell nuclear transfer (SCNT). In this study, we transferred cultured rabbit cumulus cells (RCC) and fetal fibroblasts (RFF) from genetically marked rabbits (Alicia/Basilea) into metaphase II oocytes and analyzed the levels of histone H3-lysine 9-lysine 14 acetylation (acH3K9/14) in donor cells and cloned embryos. We also assessed the correlation between the histone acetylation status of donor cells and cloned embryos and their developmental potential. To test whether alteration of the histone acetylation status affects development of cloned embryos, we treated donor cells with sodium butyrate (NaBu), a histone deacetylase inhibitor. Further, we tried to improve cloning efficiency by chimeric complementation of cloned embryos with blastomeres from in vivo fertilized or parthenogenetic embryos. The levels of acH3K9/14 were higher in RCCs than in RFFs (P!0.05). Although the type of donor cells did not affect development to blastocyst, after transfer into recipients, RCC cloned embryos induced a higher initial pregnancy rate as compared to RFF cloned embryos (40 vs 20%). However, almost all pregnancies with either type of cloned embryos were lost by the middle of gestation and only one fully developed, live RCC-derived rabbit was obtained. Treatment of RFFs with NaBu significantly increased the level of acH3K9/14 and the proportion of nuclear transfer embryos developing to blastocyst (49 vs 33% with non-treated RFF, P!0.05). The distribution of acH3K9/14 in either group of cloned embryos did not resemble that in in vivo fertilized embryos suggesting that reprogramming of this epigenetic mark is aberrant in cloned rabbit embryos and cannot be corrected by treatment of donor cells with NaBu. Aggregation of embryos cloned from NaBu-treated RFFs with blastomeres from in vivo derived embryos improved development to blastocyst, but no cloned offspring were obtained. Two live cloned rabbits were produced from this donor cell type only after aggregation of cloned embryos with a parthenogenetic blastomere. Our study demonstrates that the levels of histone acetylation in donor cells and cloned embryos correlate with their developmental potential and may be a useful epigenetic mark to predict efficiency of SCNT in rabbits.

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“…Depending on the species, the major ZGA generally occurs after two or three cleavage divisions (Telford et al ., 1990) and up to four in the rabbit embryo (Manes, 1977; Delouis et al ., 1992). In this species, although zygotic transcripts have not yet been detected before the 2‐cell stage (Cotton et al ., 1980; Kanka, 1993), the minor ZGA phase may begin at the end of the 1‐cell stage, as in the mouse (Christians et al ., 1994). The same study indicated that microinjected enhancer‐less genes are repressed after the first mitosis.…”

Section: Introductionmentioning

confidence: 99%

Nuclear translocation and carboxyl-terminal domain phosphorylation of RNA polymerase II delineate the two phases of zygotic gene activation in mammalian embryos

Bellier

Chastant-Maillard

Adenot³

et al. 1997

The EMBO Journal

102

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In mammalian embryos, zygotic gene transcription initiates after a limited number of cell divisions through a two-step process termed the zygotic gene activation (ZGA). Here we report that RNA polymerase II undergoes major changes in mouse and rabbit preimplantation embryos during the ZGA. In transcriptionally inactive unfertilized oocytes, the RNA polymerase II largest subunit is predominantly hyperphosphorylated on its carboxy-terminal domain (CTD). The CTD is markedly dephosphorylated several hours after fertilization, before the onset of a period characterized by a weak transcriptional activity. The largest subunit of RNA polymerase II then lacks immunological and drug-sensitivity characteristics related to its phosphorylation by the TFIIH-associated kinase and gradually translocates into the nuclei independently of DNA replication and mitosis. A phosphorylation pattern of the largest subunit, close to that observed in somatic cells, is established in both mouse and rabbit embryos at the stage when transcription becomes a requirement for further development (respectively at the 2-and 8/16-cell stage). As these events occurred in the presence of actinomycin D, the nuclear translocation of RNA polymerase II and the phosphorylation of the CTD might be major determinants of ZGA.

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Onset of RNA synthesis and poly (A) content of early rabbit embryos. Comparison with sheep

Cited by 14 publications

References 11 publications

Developmental failure of hybrid embryos originated after fertilization of bovine oocytes with ram spermatozoa

Developmental failure of hybrid embryos originated after fertilization of bovine oocytes with ram spermatozoa

Rabbit somatic cell cloning: effects of donor cell type, histone acetylation status and chimeric embryo complementation

Nuclear translocation and carboxyl-terminal domain phosphorylation of RNA polymerase II delineate the two phases of zygotic gene activation in mammalian embryos

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