Water-escape time in adult mice derived from manipulated preimplantation embryos

John D. Biggers; Virginia E. Papaioannou

doi:10.1007/bf01133028

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

Molecular and Cellular Biology ◽

10.1128/mcb.14.7.4694-4703.1994 ◽

1994 ◽

Vol 14 (7) ◽

pp. 4694-4703

Author(s):

E M Thompson ◽

E Christians ◽

M G Stinnakre ◽

J P Renard

Keyword(s):

Transgene Expression ◽

Developmental Stages ◽

Preimplantation Embryos ◽

Dependent Manner ◽

Cell Stage ◽

Position Effects ◽

Adult Mice ◽

Preimplantation Mouse ◽

Transgenic Lines

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.

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

Molecular and Cellular Biology ◽

10.1128/mcb.14.7.4694 ◽

1994 ◽

Vol 14 (7) ◽

pp. 4694-4703 ◽

Cited By ~ 41

Author(s):

E M Thompson ◽

E Christians ◽

M G Stinnakre ◽

J P Renard

Keyword(s):

Transgene Expression ◽

Developmental Stages ◽

Preimplantation Embryos ◽

Dependent Manner ◽

Cell Stage ◽

Position Effects ◽

Adult Mice ◽

Preimplantation Mouse ◽

Transgenic Lines

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.

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Binucleate Spermiogenesis in the Mouse

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010009381x ◽

1972 ◽

Vol 30 ◽

pp. 112-113

Author(s):

John J. Wolosewick

Keyword(s):

Electron Microscopy ◽

Phosphate Buffer ◽

Seminiferous Epithelium ◽

Mouse Testis ◽

Germinal Epithelium ◽

Intercellular Bridges ◽

Adult Mice ◽

Cervical Dislocation ◽

Human And Mouse

Classically, the male germinal epithelium is depicted as synchronously developing uninucleate spermatids conjoined by intercellular bridges. Recently, binucleate and multinucleate spermatids from human and mouse testis have been reported. The present paper describes certain developmental events in one type of binucleate spermatid in the seminiferous epithelium of the mouse.Testes of adult mice (ABP Jax) were removed from the animals after cervical dislocation and placed into 2.5% glutaraldehyde/Millonig's phosphate buffer (pH 7.2). Testicular capsules were gently split and separated, exposing the tubules. After 15 minutes the tissue was carefully cut into cubes (approx. 1mm), fixed for an additional 45 minutes and processed for electron microscopy.

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Ineffective Thrombopoiesis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100158881 ◽

1990 ◽

Vol 48 (3) ◽

pp. 266-267

Author(s):

JM Radley ◽

SL Ellis

Keyword(s):

Microscopic Examination ◽

Phosphate Buffer ◽

Primary Myelofibrosis ◽

Transient Increase ◽

Major Difficulty ◽

Adult Mice ◽

Dense Cytoplasm

In effective thrombopoies is has been inferred to occur in several disease sates from considerations of megakaryocyte mass and platelet kinetics. Microscopic examination has demonstrated increased numbers of megakaryocytes, with a typical forms particularly pronounced, in primary myelofibrosis. It has not been documented if megakaryocyte ever fail to reach maturity in non-pathological situations. A major difficulty of establishing this is that the number of megakaryocytes normally present in the marrow is extremely low. A large transient increase in megakaryocytopoiesis can how ever be induced in mice by an injection of 5-fluorouracil. We have utilised this treatment and report here evidence for in effective thrombopoies is in healthy mice.Adult mice were perfused (2% glutaraldehyde in 0.08M phosphate buffer, pH 7.4) 8 days following an injection of 5-fluorouracil (150mg/kg). Femurs were subsequently decalcified in 10% neutral E.D.T.A. and embedded in Spurrs resin. Transverse sections of marrow revealed many megakaryocytes at various stages of maturity. Occasional megakaryocytes (less than 1%) were found to be under going degeneration prior to achieving full maturation and releasing cytoplasm as platelets. These cells were characterized by a peripheral rim of dense cytoplasm which enveloped a mass of organelles and vacuoles (Fig. 1). Numerous microtubules were foundaround and with in the organelle-rich zone (Fig 2).

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