X-chromosome activity in preimplantation mouse embryos from XX and XO mothers

Development ◽  
1978 ◽  
Vol 46 (1) ◽  
pp. 53-64
Author(s):  
Marilyn Monk ◽  
Mary Harper
Keyword(s):  
X Chromosome ◽  
Bimodal Distribution ◽  
Mouse Embryos ◽  
Activity Levels ◽  
Cell Stage ◽  
X Chromosomes ◽  
Preimplantation Mouse Embryos ◽  
Preimplantation Mouse ◽  
Morula Stage ◽  
The Mean

Embryos from XO female mice begin development with half the activity levels of an enzyme (HPRT) coded for by a gene on the X chromosome, compared with embryos from XX females. Groups of unfertilized eggs and individual embryos at the 8-cell, morula and blastocyst stages were assayed for HPRT activity. An autosomally coded enzyme (APRT) was assayed simultaneously in the same reaction mix as a control. There is a substantial increase in HPRT activity by the 8-cell stage. However, the mean activity of HPRT in embryos of XO mothers remains half that in embryos of XX mothers. This suggests a significant maternally inherited component of HPRT activity in 8-cell embryos. By the 9- to 16-cell morula stage the HPRT activities in the two groups of embryos become similar due, presumably, to a transition to embryo-coded activity; HPRT activities in individual morulae from XX mothers show a bimodal distribution consistent with the hypothesis that both X-chromosomes are active in XX embryos at this stage.

Human Adenovirus Uptake by Preirnplantation Mouse Embryos

1972 ◽  
Vol 30 ◽  
pp. 268-269
Author(s):  
D. G. Chase ◽  
W. Winters ◽  
L. Piko
Keyword(s):  
Hela Cells ◽  
Human Adenovirus ◽  
Mouse Embryos ◽  
Equilibrium Density ◽  
Cell Stage ◽  
Virus Attachment ◽  
Preimplantation Mouse Embryos ◽  
Embryo Culture Medium ◽  
Preimplantation Mouse ◽  
Mouse Cells

Although the outlines of human adenovirus entry and uncoating in HeLa cells has been clarified in recent electron microscope studies, several details remain unclear or controversial. Furthermore, morphological features of early interactions of human adenovirus with non-permissive mouse cells have not been extensively documented. In the course of studies on the effects of human adenoviruses type 5 (AD-5) and type 12 on cultured preimplantation mouse embryos we have examined virus attachment, entry and uncoating. Here we present the ultrastructural findings for AD-5.AD-5 was grown in HeLa cells and purified by successive velocity gradient and equilibrium density gradient centrifugations in CsCl. After dialysis against PBS, virus was sedimented and resuspended in embryo culture medium. Embryos were placed in culture at the 2-cell stage in Brinster's medium.

Participation of glucose in the synthesis of glycoproteins in preimplantation mouse embryos

1990 ◽  
Vol 2 (1) ◽  
pp. 35 ◽  
Author(s):  
RG Wales ◽  
J Hunter
Keyword(s):  
Incubation Medium ◽  
Lactate Production ◽  
Glycogen Storage ◽  
High Concentration ◽  
Cell Stage ◽  
Glucose Carbon ◽  
Preimplantation Mouse Embryos ◽  
Preimplantation Mouse ◽  
Morula Stage ◽  
Qualitative Changes

Electrophoretic separation of solubilized embryos incubated for 24 h in the presence of [U-14C]glucose indicated incorporation of glucose carbon into a number of protein bands. Treatment of nitrocellulose blots of electrophoretograms with glucosidases had no effect on incorporated counts, confirming that the labelled bands were not due to protein bound glycogen. Furthermore, addition of 0.1 microgram mL-1 tunicamycin to the incubation medium virtually eliminated incorporation of glucose into the protein bands but had no effect on the pattern or rate of incorporation of labelled amino acids in parallel experiments. Also the pattern of labelling of protein by glucose was reflected in the pattern of binding of Con A to the nitrocellulose blots. There were quantitative and qualitative changes in labelling as development progressed. For embryos cultured from the 2-cell stage, a small amount of label was incorporated in two major bands at relative mobility (Mr) 69 and 97 K. With culture from the 8-cell stage, three additional major bands (33, 44 and 56 K) were labelled. Embryos cultured from the morula stage showed a different profile of incorporation; there was much more active labelling, and eight major and a number of minor radioactive bands were identified. Whilst tunicamycin suppressed glucose incorporation into glycoproteins and inhibited compaction of embryos, it had little effect on other parameters of metabolism during incubation in its presence for 24 h. No significant effects of the metabolite on protein synthesis, glycogen storage, lactate production or overall macromolecular synthesis were evident. By contrast, the anabolic metabolism of embryos decompacted by long periods of exposure to tunicamycin was severely reduced although glycolysis was still unaffected. Amphomycin at very high concentration (500 micrograms mL-1) was toxic to embryos but at concentrations up to 250 micrograms mL-1 had no effect on compaction and development of blastocysts. Addition of monensin to the incubation medium [16 micrograms mL-1] did not interfere with the development of either 2-cell or 8-cell embryos to blastocysts.

scholarly journals Changes in responsiveness of preimplantation mouse embryos to serum

Development ◽  
1978 ◽  
Vol 45 (1) ◽  
pp. 295-301
Author(s):  
Simon B. Fishel ◽  
M. Azim H. Surani
Keyword(s):  
Bovine Serum ◽  
Rna Synthesis ◽  
Blastocyst Stage ◽  
Mouse Embryos ◽  
The Other ◽  
Cell Stage ◽  
Preimplantation Mouse Embryos ◽  
Preimplantation Mouse ◽  
Serum Albumen

Changes in uptake of radioactive uridine and its incorporation into RNA were determined in preimplantation mouse embryos, from the 2-cell to the blastocyst stage, as a measure of their responsiveness to extracellular conditions. Two media were tested, one contained serum and the other contained bovine serum albumen as a control. An increase in the acid-soluble pool occurred at the 8-cell stage and a marked increase in RNA synthesis occurred at the early blastocyst stage when the embryos were incubated with serum.

Cell membrane regions in preimplantation mouse embryos

Development ◽  
1980 ◽  
Vol 59 (1) ◽  
pp. 89-102
Author(s):  
L. Izquierdo ◽  
T. López ◽  
P. Marticorena
Keyword(s):  
Enzyme Activity ◽  
Cell Membrane ◽  
Light And Electron Microscopy ◽  
Enzyme Reaction ◽  
Mouse Embryos ◽  
Cell Stage ◽  
Preimplantation Mouse Embryos ◽  
Preimplantation Mouse ◽  
Cortical System ◽  
Crystalloid Bodies

Cell membrane regions characterized by alkaline phosphatase activity are described in cleaving mouse embryos and early blastocysts. Enzyme activity is demonstrated by light and electron microscopy, from the late 4-cell stage onwards, on the cell surfaces between blastomeres but not on the outer surface of the embryo. Experiments with dissociated morulae show that this is probably not an artifact due to the retention of the enzyme reaction product between the blastomeres. With the electron microscope the activity is also demonstrated in crystalloid bodies within the cytoplasm. The localization and growth during cleavage of cell membrane regions with enzyme activity is interpreted as the result of new cell membrane formation and/or as a relation of the crystalloid bodies with the cell membrane through the cortical system of microtubules and filaments.

Disruption of the cytokeratin filament network in the preimplantation mouse embryo

Development ◽  
1988 ◽  
Vol 104 (2) ◽  
pp. 219-234
Author(s):  
J.A. Emerson
Keyword(s):  
Mouse Embryo ◽  
Blastocyst Stage ◽  
Cell Stage ◽  
Trophectoderm Cells ◽  
Preimplantation Mouse Embryos ◽  
Preimplantation Mouse Embryo ◽  
Preimplantation Mouse ◽  
Morula Stage ◽  
Cytokeratin Filaments

The distribution of the cytokeratin network in the intact preimplantation mouse embryo and the role of cytokeratin filaments in trophectoderm differentiation were investigated by means of whole-mount indirect immunofluorescence microscopy and microinjection of anti-cytokeratin antibody. Assembled cytokeratin filaments were detected in some blastomeres as early as the compacted 8-cell stage. The incidence and organization of cytokeratin filaments increased during the morula stage, although individual blastomeres varied in their content of assembled filaments. At the blastocyst stage, each trophectoderm cell contained an intricate network of cytokeratin filaments, and examination of sectioned blastocysts confirmed that extensive arrays of cytokeratin filaments were restricted to cells of the trophectoderm. Microinjection of anticytokeratin antibody into individual mural trophectoderm cells of expanded blastocysts resulted in a dramatic rearrangement of the cytokeratin network in these cells. Moreover, antibody injection into 2-cell embryos inhibited assembly of the cytokeratin network during the next two days of development. Despite this disruption of cytokeratin assembly, the injected embryos compacted and developed into blastocysts with normal morphology and nuclear numbers. These results suggest that formation of an elaborate cytokeratin network in preimplantation mouse embryos is unnecessary for the initial stages of trophectoderm differentiation resulting in blastocyst formation.

The effects of embryo stage and cell number on the composition of mouse aggregation chimaeras

Zygote ◽  
2000 ◽  
Vol 8 (3) ◽  
pp. 235-243 ◽  
Author(s):  
Pin-chi Tang ◽  
John D. West
Keyword(s):  
Inner Cell Mass ◽  
Cell Mass ◽  
Cell Number ◽  
Mouse Embryos ◽  
Cell Stage ◽  
Advanced Embryo ◽  
Preimplantation Mouse Embryos ◽  
Preimplantation Mouse ◽  
Cell Embryo ◽  
Embryo Stage

Studies with intact preimplantation mouse embryos and some types of chimaeric aggregates have shown that the most advanced cells are preferentially allocated to the inner cell mass (ICM) rather than the trophectoderm. Thus, differences between 4-cell and 8-cell stage embryos could contribute to the tendency for tetraploid cells to colonise the trophectoderm more readily than the ICM in 4-cell tetraploid[harr ]8 cell diploid chimaeras. The aim of the present study was to test whether 4-cell stage embryos in 4-cell diploid[harr ]8-cell diploid aggregates contributed equally to all lineages present in the E12.5 conceptus. These chimaeras were compared with those produced from standard aggregates of two whole 8-cell embryos and aggregates of half an 8-cell embryo with a whole 8-cell embryo. As expected, the overall contribution of 4-cell embryos was lower than that of 8-cell embryos and similar to that of half 8-cell stage embryos. In the 4-cell[harr ]8-cell chimaeras the 4-cell stage embryos did not contribute more to the trophectoderm than the ICM derivatives. Thus, differences between 4-cell and 8-cell embryos cannot explain the restricted tissue distribution of tetraploid cells previously reported for 4-cell tetraploid[harr ]8-cell diploid chimaeras. It is suggested that cells from the more advanced embryo are more likely to contribute to the ICM but, for technical reasons, are prevented from doing so in simple aggregates of equal numbers of whole 4-cell and whole 8-cell stage embryos.

scholarly journals The development of XO gynogenetic mouse embryos

Development ◽  
1987 ◽  
Vol 99 (3) ◽  
pp. 411-416
Author(s):  
J.R. Mann ◽  
R.H. Lovell-Badge
Keyword(s):  
X Chromosome ◽  
Mouse Embryos ◽  
Nuclear Transplantation ◽  
Normal Female ◽  
Cell Stage ◽  
X Chromosomes ◽  
Extraembryonic Membranes ◽  
Chromosome Imprinting

Diploid gynogenetic embryos, which have two sets of maternal and no paternal chromosomes, die at or soon after implantation. Since normal female embryos preferentially inactivate the paternally derived X chromosome in certain extraembryonic membranes, the inviability of diploid gynogenetic embryos might be due to difficulties in achieving an equivalent inactivation of one of their two maternally derived X chromosomes. In order to investigate this possibility, we constructed XO gynogenetic embryos by nuclear transplantation at the 1-cell stage. These XO gynogenones showed the same mortality around the time of implantation as did their XX gynogenetic counterparts. This shows that the lack of a paternally derived autosome set is sufficient to cause gynogenetic inviability at this stage. Autosomal imprinting and its possible relation to X-chromosome imprinting is discussed.

Histone macroH2A1 is concentrated in the inactive X chromosome of female preimplantation mouse embryos

Development ◽  
2000 ◽  
Vol 127 (11) ◽  
pp. 2283-2289 ◽  
Author(s):  
C. Costanzi ◽  
P. Stein ◽  
D.M. Worrad ◽  
R.M. Schultz ◽  
J.R. Pehrson
Keyword(s):  
X Chromosome ◽  
Hybrid Structure ◽  
X Inactivation ◽  
Preimplantation Embryos ◽  
Histone H2a ◽  
Mouse Development ◽  
X Chromosomes ◽  
Inactive X Chromosome ◽  
Preimplantation Mouse Embryos ◽  
Preimplantation Mouse

MacroH2As are core histone proteins with a hybrid structure consisting of a domain that closely resembles a full-length histone H2A followed by a large nonhistone domain. We recently showed that one of the macroH2A subtypes, macroH2A1.2, is concentrated in the inactive X chromosome in adult female mammals. Here we examine the timing of the association of macroH2A1.2 with the inactive X chromosome during preimplantation mouse development in order to assess the possibility that macroH2A1 participates in the initiation of X inactivation. The association of macroH2A1.2 with one of the X chromosomes was observed in 50% of blastocysts, occurring mostly, if not exclusively, in extraembryonic cells as was expected from previous studies, which indicated that X inactivation in embryonic lineages happens after implantation. Examination of earlier embryonic stages indicates that the association of macroH2A1 with the inactive X chromosome begins between the 8- and 16-cell stages. Of the changes that are known to happen during X inactivation in preimplantation embryos, the accumulation of macroH2A1 appears to be the earliest marker of the inactive X chromosome and is the only change that has been shown to occur during the period when transcriptional silencing is initiated.

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