Evidence for translation of HPRT enzyme on maternal mRNA in early mouse embryos

Development ◽  
1983 ◽  
Vol 74 (1) ◽  
pp. 15-28
Author(s):  
Mary I. Harper ◽  
Marilyn Monk
Keyword(s):  
Mouse Embryos ◽  
Common Mechanism ◽  
Cell Stage ◽  
Similar Time ◽  
Maternal Mrna ◽  
Enzyme Degradation ◽  
Preimplantation Mouse Embryos ◽  
Early Increase ◽  
Preimplantation Mouse ◽  
Early Mouse

This paper presents evidence that maternal mRNA is responsible for the early increase in HPRT activity in preimplantation mouse embryos. Increase of HPRT activity is demonstrable from as early as 6 h postfertilization when there is barely detectable synthesis of embryonic RNA. The increase is sensitive to cycloheximide and thus requires protein synthesis, whereas it is insensitive to α-amanitin and therefore independent of mRNA synthesis. These results suggest that translation of HPRT occurs on pre-existing maternal mRNA. Embryo-coded HPRT activity is detectable by the 4- to 8-cell stage when the increase in HPRT activity becomes sensitive to α-amanitin. The transition from maternal- to embryo-coded enzyme activity is completed by the time of compaction. At this stage there is an unexplained yet reproducible loss of HPRT activity. Other maternally-inherited enzymes show a marked degradation occurring at a similar time. It is possible that the enzyme degradation observed reflects some common mechanism directing the changeover from maternally-derived to embryonically-derived enzymes.

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.

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.

The role of the nucleocytoplasmic ratio in development regulation of the early mouse embryo

Development ◽  
1990 ◽  
Vol 109 (2) ◽  
pp. 323-328 ◽  
Author(s):  
S.V. Evsikov ◽  
L.M. Morozova ◽  
A.P. Solomko
Keyword(s):  
Biological Clock ◽  
Mouse Embryos ◽  
Early Mouse Embryo ◽  
Cell Divisions ◽  
Preimplantation Mouse Embryos ◽  
Preimplantation Mouse ◽  
Early Mouse ◽  
Development Regulation ◽  
Clock Mechanism

The hypothesis suggesting that the blastocoele is able to form only at a definite nucleocytoplasmic ratio was tested. We compared the development of preimplantation mouse embryos under different conditions. The results demonstrated that the start of cavitation is not dependent on the number of cell divisions. Thus, a definite nucleocytoplasmic ratio is not required for blastocoele formation to start. Our studies on embryos with microsurgically altered cytoplasm content provided evidence for the following biological clock mechanism: a change in the cell program of morphogenesis needs definite concentration of the products of a previous genetic program.

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 role of glucose and pyruvate transport in regulating nutrient utilization by preimplantation mouse embryos

Development ◽  
1988 ◽  
Vol 104 (3) ◽  
pp. 423-429
Author(s):  
D.K. Gardner ◽  
H.J. Leese
Keyword(s):  
Glucose Uptake ◽  
Kinetic Studies ◽  
Nutrient Utilization ◽  
Embryonic Cell ◽  
Mouse Embryos ◽  
Facilitated Diffusion ◽  
Cell Stage ◽  
Analytical Technique ◽  
Preimplantation Mouse Embryos ◽  
Preimplantation Mouse

Preimplantation mouse embryos utilize pyruvate preferentially during the early cleavage stages before switching to glucose at around the time of compaction. This switch in substrate preference has been studied using a non-invasive ultramicrofluorometric analytical technique on single mouse embryos. On the basis of transport kinetic studies and inhibition by phloretin, cytochalasin B and sugar analogues, a component of glucose uptake by mouse blastocysts was found to be mediated by facilitated diffusion. The Jmax and Kt of this facilitated component were 3.53 pmol embryo-1 h-1 and 0.14 mM, respectively. At physiological concentrations of glucose, the facilitated component accounts for around 75% of glucose uptake. Glucose uptake by blastocysts was found to be insensitive to insulin, added at a range of concentrations. There was no evidence for glucose active transport. The carrier-mediated component of glucose entry was detectable from the 2-cell stage onwards. Pyruvate uptake was also mediated by a carrier throughout development. In the absence of glucose in the incubation medium, the characteristic decline in pyruvate uptake does not occur. The data are consistent with a role for embryonic cell transport in regulating glucose utilization prior to compaction, but do not exclude the involvement of metabolic factors, such as the allosteric regulation of the enzymes hexokinase and phosphofructokinase.

Identification of a 2-cell stage specific inhibitor of the cleavage of preimplantation mouse embryos synthesized by rat hepatoma cells as 5′-deoxy-5′-methylthioadenosine

Zygote ◽  
2010 ◽  
Vol 19 (2) ◽  
pp. 117-125 ◽  
Author(s):  
Masayuki Kobayashi ◽  
Koichi Saito ◽  
Shigeru Tamogami ◽  
Junko Takashima ◽  
Kano Kasuga ◽  
...  
Keyword(s):  
Biological Activities ◽  
Specific Inhibitor ◽  
Biological Properties ◽  
Mouse Embryos ◽  
Cell Stage ◽  
Preimplantation Mouse Embryos ◽  
Preimplantation Mouse ◽  
Mammalian Embryos ◽  
Rat Hepatoma

SummaryRat hepatoma Reuber H-35 cells produce a unique compound designated as Fr.B-25, a 2-cell stage-specific inhibitor of the cleavage of preimplantation mouse embryos cultured in vitro. Here, we identified Fr.B-25 as a purine nucleoside, 5′-deoxy-5′-methylthioadenosine (MTA), by mass spectroscopic analysis. All of the biological activities examined of authentic MTA on the development of mouse zygotes were indistinguishable from those of Fr.B-25. The mechanism of MTA action in the development of preimplantation mouse embryos was probably different from those of hypoxanthine and adenosine, which are well-characterized purine nucleosides that act as inhibitors of the cleavage of mouse 2-cell embryos. From the shared molecular and biological properties of Fr.B-25 and MTA, we concluded that Fr.B-25 is MTA. To the best of our knowledge, this is the first delineation of the effect of MTA on the development of preimplantation mammalian embryos cultured in vitro.

The nature and distribution of serologically detectable alloantigens on the preimplantation mouse embryo

Development ◽  
1976 ◽  
Vol 35 (1) ◽  
pp. 59-72
Author(s):  
Audrey L. Muggleton-Harris ◽  
Martin H. Johnson
Keyword(s):  
Mouse Embryo ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Convincing Evidence ◽  
Mouse Embryos ◽  
Cell Type ◽  
Cell Stage ◽  
Preimplantation Mouse Embryos ◽  
Preimplantation Mouse Embryo ◽  
Preimplantation Mouse

The nature and distribution of surface alloantigens on preimplantation mouse embryos has been examined by immunofluorescence. Non-H-2 alloantigens were detected at allstages examined, from the 2-cell to the 4½-day blastocyst. Cleaving blastomeres, inner cell mass cells and cells of the primary trophectoderm were all positive. In F1 embryos maternalnon-H-2 alloantigens were detectable at all stages, whereas paternal antigens first became evident at the 6- to 8-cell stage. No convincing evidence of the presence of alloantigens associated with the H-2 haplotype was found at any stage or on any cell type, suggesting that if these antigens are present they are in low quantity or are masked.

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.

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