Patterns of RNA synthesis in early meiotic prophase oocytes from fetal mouse ovaries

Chromosoma ◽  
1978 ◽  
Vol 67 (1) ◽  
pp. 21-40 ◽  
Author(s):  
Aimee Hayes Bakken ◽  
Marsha McClanahan
Keyword(s):  
Meiotic Prophase ◽  
Rna Synthesis ◽  
Fetal Mouse

scholarly journals INORGANIC CATIONS IN THE CELL NUCLEUS

1972 ◽  
Vol 53 (2) ◽  
pp. 483-493 ◽  
Author(s):  
Laura L. Tres ◽  
A. L. Kierszenbaum ◽  
C. J. Tandler
Keyword(s):  
Meiotic Prophase ◽  
Rna Synthesis ◽  
Adult Mouse ◽  
Divalent Cations ◽  
Synthetic Activity ◽  
Inorganic Cations ◽  
Transcription Process ◽  
Inorganic Cation ◽  
Interchromatin Granules ◽  
Potassium Pyroantimonate

Earlier reports indicated the presence of significant amounts of inorganic salts in the nucleus. In the present study the possibility that this might be related to the transcription process was tested on seminiferous epithelium of the adult mouse, using potassium pyroantimonate as a fixative. The results indicated that a correlation exists between the inorganic cations comprising the pyroantimonate-precipitable fraction and the RNA synthetic activity. During meiotic prophase an accumulation of cation-antimonate precipitates occurs dispersed through the middle pachytene nuclei, the stage in which RNA synthesis reaches a maximum. At other stages (zygotene to diplotene), where RNA synthesis falls to a low level, that pattern is not seen; cation-antimonate deposits are restricted to a few masses in areas apparently free of chromatin. The condensed sex chromosomes, the heterochromatin of the "basal knobs," the axial elements, and the synaptonemal complexes are devoid of antimonate deposits during the meiotic prophase. The Sertoli cells, active in RNA synthesis in both nucleoplasm and nucleolus, show cation-antimonate deposits at these sites. In the nucleoplasm some "patches" of precipitates appear coincident with clusters of interchromatin granules; in the nucleolus the inorganic cations are mainly located in the fibrillar and/or amorphous areas, whereas relatively few are shown by the granular component. The condensed chromatin bodies associated with the nucleolus were always free of antimonate precipitates. It is suggested that the observed sites of inorganic cation accumulation within the nucleus may at least partially indicate the presence of RNA polymerases, the activity of which is dependent on divalent cations.

scholarly journals NUCLEOLAR AND PERICHROMOSOMAL RNA SYNTHESIS DURING MEIOTIC PROPHASE IN THE MOUSE TESTIS

1974 ◽  
Vol 60 (1) ◽  
pp. 39-53 ◽  
Author(s):  
A. L. Kierszenbaum ◽  
Laura L. Tres
Keyword(s):  
Sex Chromosomes ◽  
Meiotic Prophase ◽  
Rna Synthesis ◽  
Transcriptional Activity ◽  
Mouse Testis ◽  
Synthetic Activity ◽  
Synthetic Cell ◽  
Nucleolar Organizers ◽  
Nucleolar Rna ◽  
Silver Grains

The transcriptional activity during meiotic prophase in the mouse testis is studied with light microscopy and high-resolution autoradiographic techniques using [3H]uridine as a labeled precursor. In the present study, two types of RNA synthesis are detected during meiotic prophase: an extranucleolar RNA synthesis of perichromosomal localization and a nucleolar RNA synthetic activity. In some of the autosomes and close to the basal knobs, the activity of the nucleolar organizers is evidenced by the incorporation of [3H]uridine into nucleolar masses from zygotene on and at earlier labeling times. The evolution of nucleoli and the formation of a nucleolus attached to the sex pair are described during the different meiotic stages. Perichromosomal labeling, from leptotene on, reaches a maximum during middle pachytene and falls progressively to a low level at longer incorporation times. Sertoli's cell, the most active RNA synthetic cell in the seminiferous epithelium, rises to a maximum of labeling and drops at earlier times compared with the meiotic prophase cells. The condensed sex chromosomes show some scattered silver grains especially at middle pachytene. The axial chromosome cores and synaptonemal complexes are devoid of silver grains during the meiotic prophase. The observations suggest that a control mechanism operates during meiotic prophase to regulate transcriptional activity in the sex chromosomes and to provide differential RNA synthesis in autosomal bivalents at various stages of prophase and within certain segments of the chromosomes.

scholarly journals TRANSCRIPTION SITES IN SPREAD MEIOTIC PROPHASE CHROMOSOMES FROM MOUSE SPERMATOCYTES

1974 ◽  
Vol 63 (3) ◽  
pp. 923-935 ◽  
Author(s):  
A. L. Kierszenbaum ◽  
Laura L. Tres
Keyword(s):  
Gene Expression ◽  
Meiotic Prophase ◽  
Rna Synthesis ◽  
Sex Chromosome ◽  
Nucleolar Organizer ◽  
Structural Elements ◽  
Autosomal Bivalents ◽  
Whole Mount ◽  
Nuclear Rna ◽  
Transcription Sites

Mouse spermatocytes at pachytene stage have been examined by whole-mount electron microscope techniques complemented with autoradiography as an approach for visualizing their transcriptive activity. Structural elements of meiotic bivalents, such as synaptonemal complexes and chromatin fibers, have been satisfactorily displayed in the total set of autosomal and sexual bivalents in single spermatocytes. Adequate preservation of the entire set of bivalents has provided a basis for recognition of sites where presumptive preribosomal RNA and heterogeneous nuclear RNA species are being transcribed at different segments of autosomal bivalents. Nucleoli attached to the basal knob region where nucleolar organizer cistrons are assumed to be located and ribonucleoprotein fibrils associated with distinct chromatin loops have been recognized. These structural findings have been correlated with display of [3H]uridine incorporation sites in thin-section and whole-mount electron microscopy autoradiographic preparations. A low transcriptive activity of the sexual bivalent contrasted with extensive gene expression in autosomal bivalents. Each sex chromosome shows a double axial core. A short region of pairing with a synaptonemal complex joins the two chromosomes at one end. We conclude that variations in the rate of RNA synthesis throughout meiotic prophase stages in the mouse are expressed as fluctuations in the amount and distribution of distinct RNA species at specific segments of the bivalents.

The nucleolus and meiosis during microsporogenesis in Endymion non-scriptus (L.)

1977 ◽  
Vol 25 (1) ◽  
pp. 111-123
Author(s):  
B.T. Luck ◽  
E.G. Jordan
Keyword(s):  
Electron Microscopy ◽  
Meiotic Prophase ◽  
Rna Synthesis ◽  
Nuclear Division ◽  
Structural Transformations ◽  
Nucleolus Organizer ◽  
Fibrillar Region ◽  
Nucleolus Organizers

Stages of meiosis from the bluebell Endymion non-scriptus (L.) were studied by electron microscopy. The segregated components of the nucleolus at meiotic prophase underwent fragmentation and dissolution at pachytene-diplotene. Nucleoli were absent during both meiotic divisions and reformed on the nucleolus organizer into a fibrillar mass from scattered fibrillar components at the dyad and tetrad stages. Ti is argued that the fibrillar region shows continuity through nuclear division though undergoing structural transformations in the process. Nucleolar reformation occurs on condensed nucleolus organizers. Processing of the ribosomal precursors and the resumption of RNA synthesis is discussed in relation to the dispersal of the nucleolus organizer into the fibrillar region of the reformed nucleolus.

Effect of Some Metabolic Inhibitors on Vinblastine-Induced Ribosomal-Granular Material Complexes

1971 ◽  
Vol 29 ◽  
pp. 548-549
Author(s):  
Awtar Krishan ◽  
Dora Hsu
Keyword(s):  
Granular Material ◽  
Rna Synthesis ◽  
Culture Medium ◽  
Actinomycin D ◽  
Metabolic Inhibitors ◽  
Protein And Rna Synthesis ◽  
Apparent Reduction ◽  
Plant Alkaloids ◽  
In Cells

Cells exposed to antitumor plant alkaloids, vinblastine and vincristine sulfate have large proteinacious crystals and complexes of ribosomes, helical polyribosomes and electron-dense granular material (ribosomal complexes) in their cytoplasm, Binding of H3-colchicine by the in vivo crystals shows that they contain microtubular proteins. Association of ribosomal complexes with the crystals suggests that these structures may be interrelated.In the present study cultured human leukemic lymphoblasts (CCRF-CEM), were incubated with protein and RNA-synthesis inhibitors, p. fluorophenylalanine, puromycin, cycloheximide or actinomycin-D before the addition of crystal-inducing doses of vinblastine to the culture medium. None of these compounds could completely prevent the formation of the ribosomal complexes or the crystals. However, in cells pre-incubated with puromycin, cycloheximide, or actinomycin-D, a reduction in the number and size of the ribosomal complexes was seen. Large helical polyribosomes were absent in the ribosomal complexes of cells treated with puromycin, while in cells exposed to cycloheximide, there was an apparent reduction in the number of ribosomes associated with the ribosomal complexes (Fig. 2).

Ultrastructural alterations in the fetal mouse myocardium in response to genetic and environmental factors

1987 ◽  
Vol 45 ◽  
pp. 724-725
Author(s):  
K.C. Feng-Chen ◽  
F.B. Essien ◽  
K.J. Prestwidge ◽  
J.T. Cheng ◽  
C.L. Shen
Keyword(s):  
Fetal Heart ◽  
Perinatal Period ◽  
Primary Energy ◽  
Cardiac Contraction ◽  
Ultrastructural Changes ◽  
Fetal Mouse ◽  
The Subject ◽  
Physiological Adjustments ◽  
Genetic And Environmental Factors ◽  
Genetically Determined

The physiology of the fetal heart differs significantly from that of the mature post-natal organ: e.g., the metabolic supply for adult cardiac contraction relies mainly on fatty acids; whereas, the fetal heart uses carbohydrates as its primary energy source. Limited morphological descriptions of the developing myocardium have appeared. However, additional studies are required to elucidate the ultrastructural changes occuring in the perinatal period when enormous physiological adjustments are made. Although adult animals are most often used in toxocological and pathological analyses, it is also important to investigate fetal cardiac responsiveness to various agents. The vulnerability of the ultrastructure of the fetal mouse myocardium to genetic and environmental assault is the subject of this report. The genetically determined effect on the heart was observed in mouse embryos homozygous for the cab (cardiac abnormality) mutation discovered by Essien.

Antagonist-induced opiate receptor upregulation in cultures of fetal mouse spinal cord-ganglion explants

1986 ◽  
Vol 390 (2) ◽  
pp. 287-291 ◽  
Author(s):  
A TEMPEL ◽  
S CRAIN ◽  
E PETERSON ◽  
E SIMON ◽  
R SUZANNEZUKIN
Keyword(s):  
Spinal Cord ◽  
Opiate Receptor ◽  
Fetal Mouse ◽  
Mouse Spinal Cord ◽  
Receptor Upregulation
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