scholarly journals Scaffold attachment regions stimulate HSP70.1 expression in mouse preimplantation embryos but not in differentiated tissues.

1994 ◽  
Vol 14 (7) ◽  
pp. 4694-4703 ◽  
Author(s):  
E M Thompson ◽  
E Christians ◽  
M G Stinnakre ◽  
J P Renard

Eukaryotic interphase chromatin is thought to be organized into topologically discrete, independent domains acting as units upon which differential patterns of gene expression are established. Sequences which attach chromatin to in vitro preparations of a nucleoprotein matrix (scaffold attachment regions [SARs]) may act as domain boundaries, but their role remains poorly defined compared with those of other elements such as locus control regions. We have produced mice homozygous for a transgene which is transcribed as early as the activation of the embryonic genome at the two-cell stage and which is expressed ubiquitously in a number of differentiated tissues. Transgenic lines were generated in the presence or absence of flanking SAR sequences, creating an original model which enabled us to examine the effects of these elements at different developmental stages. In the preimplantation mouse embryo, flanking SARs stimulated transgene expression in a copy-dependent manner. In contrast, in the differentiated tissues of newborn and adult mice, no significant SAR-dependent increase in transgene expression was found, correlation with copy number was lost, and position effects were observed. These results suggest a limited capacity of SARs to act as insulating elements but are consistent with a proposed model of SAR-mediated chromatin opening and closing.

1994 ◽  
Vol 14 (7) ◽  
pp. 4694-4703
Author(s):  
E M Thompson ◽  
E Christians ◽  
M G Stinnakre ◽  
J P Renard

Eukaryotic interphase chromatin is thought to be organized into topologically discrete, independent domains acting as units upon which differential patterns of gene expression are established. Sequences which attach chromatin to in vitro preparations of a nucleoprotein matrix (scaffold attachment regions [SARs]) may act as domain boundaries, but their role remains poorly defined compared with those of other elements such as locus control regions. We have produced mice homozygous for a transgene which is transcribed as early as the activation of the embryonic genome at the two-cell stage and which is expressed ubiquitously in a number of differentiated tissues. Transgenic lines were generated in the presence or absence of flanking SAR sequences, creating an original model which enabled us to examine the effects of these elements at different developmental stages. In the preimplantation mouse embryo, flanking SARs stimulated transgene expression in a copy-dependent manner. In contrast, in the differentiated tissues of newborn and adult mice, no significant SAR-dependent increase in transgene expression was found, correlation with copy number was lost, and position effects were observed. These results suggest a limited capacity of SARs to act as insulating elements but are consistent with a proposed model of SAR-mediated chromatin opening and closing.


2008 ◽  
Vol 20 (1) ◽  
pp. 169 ◽  
Author(s):  
C. E. McHughes ◽  
G. K. Springer ◽  
L. D. Spate ◽  
R. Li ◽  
R. J. Woods ◽  
...  

Identification of transcripts that are present at key development stages of preimplantation embryos is critical for a better understanding of early embryogenesis. To that end, this project had two goals. The first was to characterize the relative abundance of multiple transcripts during several developmental stages, including metaphase II-stage oocytes (MPII), and 2-cell-stage (2-cell), precompact morula (PCM), and in vitro-produced blastocyst-stage (IVTBL) embryos. The second was to characterize differences in the relative abundance of transcripts present in in vivo- (IVVBL), in vitro-, and nuclear transfer-produced (NTBL) blastocysts. It was our hypothesis that the identification of differentially represented transcripts from these stages would reveal not only developmentally important genes, but also genes that might be aberrantly expressed due to embryo production techniques. Individual clusters from a large bovine EST project (http://genome.rnet.missouri.edu/Bovine/), which focused on female reproductive tissues and embryos, were compared using Fisher's exact test weighted by number of transcripts per tissue by gene (SAS PROC FREQ; SAS Institute, Inc., Cary, NC, USA). Of the 3144 transcripts that were present during embryogenesis, 125 were found to be differentially represented (P < 0.01) in at least one pairwise comparison (Table 1). Some transcripts found to increase in representation from the MPII to the 2-cell stage include protein kinases, PRKACA and CKS1, as well as the metabolism-related gene, PTTG1. These same transcripts were also found to decrease in representation from the 2-cell to the PCM stage. RPL15 (translation) and FTH1 (immune function) were both more highly represented in the PCM than in the 2-cell stage. From PCM to IVTBL, we saw an increase in RPS11, another translation-related transcript. When comparing blastocyst-stage embryos from different production techniques, several transcripts involved in energy production (e.g., COX7B and COX8A) were found to be more highly represented in the NTBL than in the IVTBL. COX8A was also more highly represented in the IVVBL than in the IVTBL. By investigating these differentially represented transcripts, we will be able to better understand the developmental implications of embryo manipulation. We may also be able to better develop reproductive technologies that lead to in vitro- and nuclear transfer-derived embryos which more closely follow a normal program of development. Table 1. Differentially represented transcripts between developmental stages


Author(s):  
Sepideh Khalili-Savadkouhi ◽  
Abbasali Karimpour Malekshah ◽  
Mehri Mirhoseini ◽  
Mahmood Moosazadeh ◽  
Maryam Shahidi

Background: In vitro culture of mammalian embryos can slow or stop growth completely. This may be due to the medium used, pH, temperature, or light. There is considerable concern about the harmful effect of light in the laboratory environment. Cell number and apoptosis are useful parameters that indicate embryonic development and health. In this study, we assessed these two factors in the blastocyst. Materials and methods: A total of 128 embryos were extracted from NMRI mice at the 2-cell stage and were divided into 4 groups. The embryos were exposed to light for 0, 5, 15, and 30 min, and then cultured for 96 h. The degree of embryonic development were recorded every 24 h. Furthermore, several morphologically normal blastocysts were evaluated using the TUNEL assay. Results: There was no significant difference in developmental stages between the experimental and control groups. An evaluation of the percentage of blastomeres and apoptotic cells revealed significant differences among the four groups. The maximum number of apoptotic blastomeres was observed in the group exposed to light for 30 minutes. Conclusion: Up to thirty minutes of white fluorescent light can induce apoptosis in blastomeres, but it does not prevent embryo development.


Reproduction ◽  
2020 ◽  
Vol 160 (2) ◽  
pp. 181-191 ◽  
Author(s):  
Satoko Kanzaki ◽  
Shiori Tamura ◽  
Toshiaki Ito ◽  
Mizuki Wakabayashi ◽  
Koji Saito ◽  
...  

Nucleotide-binding oligomerization domain, leucine-rich repeat and pyrin domain-containing proteins (NRLPs) are central components of the inflammasome. Accumulating evidence has shown that a reproductive clade of NRLPs is predominantly expressed in oocyte to cleavage stage embryos and participates in mammalian preimplantation development as a component of a multiprotein complex known as the subcortical maternal complex (SCMC). Nlrp9s belong to the reproductive class of NLRPs; Nlrp9b is unique in acting as an inflammasome against rotavirus in intestines. Here we generated mice carrying mutations in all three members of the Nlrp9a/b/c gene (Nlrp9 triple mutant (TMut) mice). When crossed with WT males, the Nlrp9 TMut females were fertile, but deliveries with fewer pups were increased in the mutants. Consistent with this, blastocyst development was retarded and lethality to the preimplantation embryos increased in the Nlrp9 TMut females in vivo. Under in vitro culture conditions, the fertilized eggs from the Nlrp9 TMut females exhibited developmental arrest at the two-cell stage, accompanied by asymmetric cell division. By contrast, double-mutant (DMut) oocytes (any genetic combination) did not exhibit the two-cell block in vitro, showing the functional redundancy of Nlrp9a/b/c. Finally, Nlrp9 could bind to components of the SCMC. These results show that Nlrp9 functions as an immune or reproductive NLRP in a cell-type-dependent manner.


Zygote ◽  
2014 ◽  
Vol 23 (4) ◽  
pp. 485-493 ◽  
Author(s):  
A.F. Pereira ◽  
L.M. Melo ◽  
V.J.F. Freitas ◽  
D.F. Salamone

SummaryIn vitro embryo production methods induce DNA damage in the embryos. In response to these injuries, histone H2AX is phosphorylated (γH2AX) and forms foci at the sites of DNA breaks to recruit repair proteins. In this work, we quantified the DNA damage in bovine embryos undergoing parthenogenetic activation (PA), in vitro fertilization (IVF) or somatic cell nuclear transfer (SCNT) by measuring γH2AX accumulation at different developmental stages: 1-cell, 2-cell and blastocyst. At the 1-cell stage, IVF embryos exhibited a greater number of γH2AX foci (606.1 ± 103.2) and greater area of γH2AX staining (12923.6 ± 3214.1) than did PA and SCNT embryos. No differences at the 2-cell stage were observed among embryo types. Although PA, IVF and SCNT were associated with different blastocyst formation rates (31.1%, 19.7% and 8.3%, P < 0.05), no differences in the number of γH2AX foci or area were detected among the treatments. γH2AX is detected in bovine preimplantation embryos produced by PA, IVF and SCNT; the amount of DNA damage was comparable among those embryos developing to the blastocyst stage among different methods for in vitro embryo production. While IVF resulted in increased damage at the 1-cell embryo stage, no difference was observed between PA and SCNT embryos at any developmental stage. The decrease in the number of double-stranded breaks at the blastocyst stage seems to indicate that DNA repair mechanisms are functional during embryo development.


Zygote ◽  
1993 ◽  
Vol 1 (3) ◽  
pp. 225-229 ◽  
Author(s):  
Francesca Vidal ◽  
Juan Hidalgo

The effect of zinc and copper on the in vitro development of mouse preimplantation embryos and on metallothionein (MT) levels was studied by exposing the embryos to 100 μM concentrations of the metals for 24 h at the 1-cell,2-cell, 6-8-cell, morula and blastocyst stages. Zinc affected embryo development in the early but not in the late stages, whereas copper affected it more generally. The combined presence of both metals caused a stronger embryotoxicity. MT levels were measured by radioimmunoassay and were found to be similar at all developmental stages, though possibly higher at the blastocyst stage. The exposure of embryos to zinc and copper increased MT levels significantly only at the blastocyst stage, supporting previously published results on MT mRNA levels.


1996 ◽  
Vol 8 (6) ◽  
pp. 945 ◽  
Author(s):  
RJ Partridge ◽  
HJ Leese

Bovine embryos produced in vitro from the putative zygote stage to the blastocyst stage, and blastocysts freshly flushed from the uterus, were cultured in a physiological mixture of amino acids. Depletion of amino acids from the medium and, in a few cases, their appearance, was measured by high performance liquid chromatography. Amino acids were depleted at widely differing rates. The depletion of amino acids was higher when embryos at later developmental stages were cultured, implying an increase in amino acid requirement with development. Threonine was the only amino acid to be depleted at all stages of development; depletion increased from 0.18 +/- 0.07 pmol embryo-1 h-1 at the putative zygote stage to 1.96 +/- 0.49 pmol embryo-1 h-1 at the blastocyst stage. Glutamine was depleted at the putative zygote stage and the 4-cell stage (0.76 +/- 0.05 and 0.94 +/- 0.10 pmol embryo-1 h-1 respectively), but was not significantly depleted at the later stages. Alanine was the only amino acid that appeared consistently in the medium and its production increased progressively throughout development. Aspartate, glutamate, threonine and lysine were depleted significantly by blastocysts derived both in vitro and in vivo; the embryos in vivo also depleted arginine, phenylalanine, isoleucine and tyrosine. These results indicate that individual amino acids are depleted at different rates by bovine preimplantation embryos and suggest that amino acid requirements change during development.


Development ◽  
1972 ◽  
Vol 27 (2) ◽  
pp. 431-445
Author(s):  
P. Barlow ◽  
D. A. J. Owen ◽  
Chris Graham

Strain PO preimplantation embryos were labelled with [3H]thymidine. The incorporation of the label was studied by autoradiography of air-dried and serially sectioned embryos. DNA amounts were measured with a microdensitometer. The following observations were made at the 5- to 16-cell stages. All nuclei contained 2C–4C amounts of DNA and all could eventually synthesize DNA. However, after short labelling intervals, unlabelled nuclei were found with 2C and AC amounts of DNA. We concluded that both the G1 and the G2 phases of the cell cycle were present at this time. Embryos were found in which the S phase of the 4th and the 5th cell cycles post fertilization overlapped. In 12- to 15-cell embryos which contained inside cells it was found that the inside cells were produced by one of the first four 8-cell-stage blastomeres to divide. The inside cells of 9- to 256-cell embryos had a significantly higher labelling index than the outside cells and the number of inside cells increased faster than the number of outside cells during development. We concluded that the inside cells were dividing faster than the outside cells. Blastocysts which had developed in vivo or in vitro contained nuclei with greater than 4C amounts of DNA. We concluded that the development of excess DNA amounts does not depend on the maternal environment. These nuclei which contained greater than 4C amounts of DNA were labelled after short exposures to radioactivity. We concluded that it was likely that they were becoming polyploid.


1994 ◽  
Vol 6 (2) ◽  
pp. 229 ◽  
Author(s):  
K Turner ◽  
AW Rogers ◽  
EA Lenton

The dry mass of mouse embryos cultured in vitro in medium alone or in an organ culture system were measured by means of the Vickers M86 scanning microinterferometer. The data were compared with previous data on the dry mass of preimplantation embryos in vivo. The metabolism of embryos cultured in vitro differs from that of fresh embryos. In cultured embryos, dry mass decreases throughout the 2-cell stage whereas the dry mass is increasing at this stage in vivo. Embryos in an organ culture system regain a dry mass profile, similar to that observed in vivo at the late cleavage stage. These results support the view that conditions for embryo metabolism are suboptimal in vitro and that, although the oviduct may confer some advantage on developing embryos in vitro, it is unable fully to support the pattern of metabolism, as assessed by dry mass, observed in vivo.


Reproduction ◽  
2004 ◽  
Vol 128 (3) ◽  
pp. 301-311 ◽  
Author(s):  
Paolo Rinaudo ◽  
Richard M Schultz

Culture of preimplantation embryos affects gene expression. The magnitude of the effect on the global pattern of gene expression, however, is not known. We compared global patterns of gene expression in blastocysts cultured from the one-cell stage in either Whitten’s medium or KSOM + amino acids (KSOM/AA) with that of blastocysts that developed in vivo, using the Affymetrix MOE430A chip. The analysis revealed that expression of 114 genes was affected after culture in Whitten’s medium, whereas only 29 genes were mis-expressed after culture in KSOM/AA. Expression Analysis Systematic Explorer was used to identify biological and molecular processes that are perturbed after culture and indicated that genes involved in protein synthesis, cell proliferation and transporter function were down-regulated after culture in Whitten’s medium. A common set of genes involved in transporter function was also down-regulated after culture in KSOM/AA. These results provide insights as to why embryos develop better in KSOM/AA than in Whitten’s medium, and highlight the power of microarray analysis to assess global patterns of gene expression.


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