Staining Whole Mouse Embryos for  -Galactosidase (lacZ) Activity

In the present study, we have analysed the expression pattern of a lacZ transgene (CMZ12) in preimplantation stage mouse embryos. The transgene is expressed at the two-cell stage, where it shows cellular mosaicism due to variable expressivity. The variable gene expression indicates a partial penetrance of the transgene. The extent of variation in expression is influenced by the genetic background of the oocyte. DBA/2 and CFLP genetic backgrounds promote high expression of the transgene, while Balb/c, C57BL/6, DDK, and F1(C57BL/6 × CBA) genetic backgrounds give none or very little lacZ activity. In vitro culture of one-cell embryos to the two-cell stage induces the expression of lacZ in all strain backgrounds tested. The variation in CMZ12 expression is a transient phenomenon and does not affect later stage activity of the transgene. Nuclear transfer experiments and DNA methylation analysis suggests that a heritable modification of the transgene locus has not occurred.Key words: cellular mosaicism, lacZ transgene, mouse embryos, variable expressivity.

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Human Adenovirus Uptake by Preirnplantation Mouse Embryos

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100094607 ◽

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.

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Preplate neurons in embryonic mouse cortex: Ultrastructural observations using photoconversion of the fluorescent lipophilic dye dil

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100124938 ◽

1992 ◽

Vol 50 (1) ◽

pp. 906-907

Author(s):

Linda C. Hassinger ◽

James E. Crandall

Keyword(s):

Mouse Embryos ◽

Embryonic Mouse ◽

Cortical Afferents ◽

Mouse Cortex ◽

Carbocyanine Dye ◽

Increased Sensitivity

We have begun to look directly at small numbers of afferent axons to early generated neurons that form the preplate in the developing mouse cortex. The carbocyanine dye Dil (1’1, dioctadecyl-3,3,3’3’-tetramethyl-indocarbocyanine) has proved especially useful for this goal. DiI labels axons and their terminals with greater sensitivity and without some of the disadvantages of axon filling with HRP. The increased sensitivity provided by labeling embryonic axons with DiI has given us new insights into the development of cortical afferents. For instance, we reported originally that afferents from the thalamus were present below the cortex as early as embryonic day 15 (E15) based on HRP injections into mouse embryos. By using DiI placements into the thalamus in aldehyde-fixed brains, we now know that thalamic fibers reach the cortex 24 hrs earlier.

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Localization of Intracisternal a Particle Antigens in Neoplastic Cells and Preimplantation Mouse Embryos

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s1431927600003044 ◽

1980 ◽

Vol 38 ◽

pp. 696-697

Author(s):

Thomas T.F. Huang ◽

Patricia G. Calarco

Keyword(s):

Endoplasmic Reticulum ◽

Normal Development ◽

Mouse Embryos ◽

Neoplastic Cells ◽

Large Numbers ◽

Preimplantation Mouse Embryos ◽

Preimplantation Mouse ◽

Intracisternal A Particle ◽

Normal Feature

The stage specific appearance of a retravirus, termed the Intracisternal A particle (IAP) is a normal feature of early preimplantation development. To date, all feral and laboratory strains of Mus musculus and even Asian species such as Mus cervicolor and Mus pahari express the particles during the 2-8 cell stages. IAP form by budding into the endoplasmic reticulum and appear singly or as groups of donut-shaped particles within the cisternae (fig. 1). IAP are also produced in large numbers in several neoplastic cells such as certain plasmacytomas and rhabdomyosarcomas. The role of IAP, either in normal development or in neoplastic behavior, is unknown.

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