scholarly journals STUDIES ON THE SITE OF SYNTHESIS OF SEVERAL SOLUBLE ENZYMES OF THE CELL NUCLEUS

1971 ◽  
Vol 50 (1) ◽  
pp. 1-9 ◽  
Author(s):  
LeRoy Kuehl ◽  
Earl N. Sumsion
Keyword(s):  
Cell Nucleus ◽  
Gel Electrophoresis ◽  
Lactic Dehydrogenase ◽  
Nuclear Proteins ◽  
Enzyme Treatment ◽  
Cytoplasmic Enzyme ◽  
Cytoplasmic Proteins ◽  
Short Period ◽  
Specific Activities ◽  
Soluble Enzymes

Rats were given radioactive L-leucine intravenously. At various times after injection, the livers were removed and separated into nuclear and cytoplasmic fractions by a nonaqueous technique. Glyceraldehyde-3-phosphate dehydrogenase, aldolase, and lactic dehydrogenase were isolated from each cell fraction by antibody precipitation followed by gel electrophoresis, and the specific radioactivities of the isolated enzymes were determined. In all three cases, the onset of labeling and the rate of incorporation were the same for the nuclear enzyme as for the corresponding enzyme from the cytoplasm. If we assume that equilibration of the enzymes between the cytoplasmic and nuclear pools occurs slowly relative to the labeling times employed, we may conclude that the labeled nuclear enzymes either were synthesized in the nucleus or moved into the nucleus from a cytoplasmic site of synthesis without first passing into the cytoplasmic pool of enzyme. Treatment with puromycin, an antibiotic which depresses incorporation into cytoplasmic proteins to a greater extent than into nuclear proteins, led to a situation in which the specific activities of the nuclear enzymes were several times as high as those of the corresponding cytoplasmic enzymes following a short period of incorporation. These data substantiate the assumption that equilibration between the cytoplasmic and nuclear enzyme pools occurs slowly and provide further evidence that the labeled nuclear enzymes do not arise from the cytoplasmic enzyme pool.

Synthesis of nuclear and cytoplasmic proteins in the early development of fishes and echinoderms

Development ◽  
1971 ◽  
Vol 26 (3) ◽  
pp. 611-622
Author(s):  
Maya R. Krigsgaber ◽  
Alla A. Kostomarova ◽  
Tamara A. Terekhova ◽  
Tatiana A. Burakova
Keyword(s):  
Amino Acids ◽  
Early Development ◽  
Sea Urchin ◽  
Nuclear Volume ◽  
Sea Urchin Embryos ◽  
Cytoplasmic Proteins ◽  
Specific Activities ◽  
Strongylocentrotus Nudus ◽  
Silver Grains ◽  
Misgurnus Fossilis

Synthesis of nuclear and cytoplasmic proteins was studied biochemically and autoradiographically in early loach (Misgurnus fossilis) and sea-urchin (Strongylocentrotus nudus) embryos. After incubation with [14C]amino acids for 5–120 min the ratio of the specific activities of nuclear, mitochondrial and 12000 g supernatant proteins was shown to be equal approximately to 6:1:2 in loach embryos and to 8:4:3 in sea-urchin embryos independently of the duration of labelling. After incubation with [3H]amino acids the number of silver grains per unit section was on the average 2·4 times higher for nuclei than it was for cytoplasm at mid-blastula and mid-gastrula stages. At the mid-gastrula the vegeto-animal gradient of protein synthesis was found. A higher level of the synthesis of nuclear proteins as compared with that of cytoplasmic proteins appears to be related to an increase in the nuclear volume and the nucleo-cytoplasmic ratio during the early development of the loach and sea-urchin embryos.

The influence of the nucleus on sequential determination in frog ectoderm following induction by lithium ion

Development ◽  
1969 ◽  
Vol 21 (3) ◽  
pp. 383-390
Author(s):  
Krystyna D. Ansevin
Keyword(s):  
Cell Nucleus ◽  
Cellular Differentiation ◽  
Intrinsic Factor ◽  
Lithium Ion ◽  
Morphological Differentiation ◽  
Competent Cell ◽  
Cell Cytoplasm ◽  
Sequential Determination ◽  
Complex Sequence ◽  
Short Period

It appears certain that the process of cellular differentiation is an outcome of interactions between the cell nucleus and cell cytoplasm. Differentiation of embryonic amphibian ectoderm involves two fairly distinct phases: during the first short period an inductor (or some intrinsic factor, if an inductor is absent) determines the course of future differentiation in a multipotential cell; during the second, longer interval of time presumably a complex sequence of reactions leads to physiological and morphological differentiation. Little is known about the nature of reactions which take place during the first phase when the cells become developmentally determined by the inductor. It appears that the first step in translation of the inductive instruction in the competent cell is accomplished during the first 2 or 3 h following the treatment with the inductor (Ansevin, 1966). The step is not actinomycin-sensitive (Ansevin, 1965), as was shown by cells that completely recovered after actinomycin treatment (in conditions when it was unlikely that they could have failed to take up some inhibitor).

Plasma Membrane and Nuclear Proteins of the Goose Erythrocyte

1973 ◽  
Vol 51 (10) ◽  
pp. 1442-1447 ◽  
Author(s):  
Keith R. Shelton
Keyword(s):  
Molecular Weight ◽  
Plasma Membrane ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Nuclear Proteins ◽  
Nuclear Fraction ◽  
Nonhistone Protein ◽  
Large Molecular Weight ◽  
Goose Erythrocyte

Plasma membrane and nuclear fractions have been prepared from mature goose erythrocytes. Examination of the nonhistone protein of the nuclear fraction by sodium dodecyl sulphate – polyacrylamide gel electrophoresis reveals a limited number of molecular weight species some of which are peculiar to the nuclear fraction.Electrophoretic comparison of the goose plasma membrane proteins with those of the human erythrocyte reveals many similarities. In particular, three large molecular weight species occur in both cells. Their function appears to predate the evolutionary loss of the nucleus.

scholarly journals Multiple growth-associated nuclear proteins immunoprecipitated by antisera raised against human c-myc peptide antigens.

1986 ◽  
Vol 6 (3) ◽  
pp. 942-949 ◽  
Author(s):  
H Persson ◽  
H E Gray ◽  
F Godeau ◽  
S Braunhut ◽  
A R Bellvé
Keyword(s):  
Sodium Dodecyl Sulfate ◽  
Nuclear Localization ◽  
Cell Nucleus ◽  
Sodium Dodecyl ◽  
Nuclear Proteins ◽  
Immunofluorescent Staining ◽  
Nuclear Staining ◽  
Polyacrylamide Gels ◽  
Peptide Antigens ◽  
Molecular Masses

Different antisera raised against various regions of the human c-myc protein were used to identify four human c-myc proteins with apparent molecular masses in sodium dodecyl sulfate-polyacrylamide gels ranging from 64 to 68 kilodaltons (phosphoproteins pp64 and pp67 and nonphosphorylated proteins p65 and p68). pp64 and p65 were the major detectable c-myc proteins, and pp67 and p68 were minor but specific components of the immunoprecipitates. The c-myc proteins were all localized in the cell nucleus. Accumulation of [35S]methionine-labeled p65 was observed after pulse-labeling and chase, suggesting that the stable p65 c-myc protein is generated posttranslationally from short-lived precursors. pp64, pp67, and p68 possessed short half-lives and may therefore be precursors of the stable p65. Confirmation of the nuclear localization of the human c-myc proteins was obtained by immunofluorescent staining. The human c-myc proteins were revealed as a pattern of punctate nuclear staining with, particularly for p65, nucleolar enhancement that left an unstained annulus surrounding the nucleolus.

scholarly journals Isolation and electrophoretic analysis of nucleoli, phenol-soluble nuclear proteins, and outer cyst walls from Acanthamoeba castellanii during encystation initiation.

1976 ◽  
Vol 68 (3) ◽  
pp. 740-751 ◽  
Author(s):  
R W Rubin ◽  
M C Hill ◽  
P Hepworth ◽  
J Boehmer
Keyword(s):  
Gel Electrophoresis ◽  
Acanthamoeba Castellanii ◽  
Electrophoretic Analysis ◽  
Growth Cycle ◽  
Nuclear Proteins ◽  
Whole Cells ◽  
Nucleolar Proteins ◽  
Transmission Electron ◽  
Identical Manner ◽  
Triton X

A technique is described for isolating nuceoli from Acanthamoeba castellanii. Nuclei isolated by a modification of the technique of F. J. Chlapowski and R. N. Band (1971) are sonicated in a surcrose-Tris-MgSO4-KC1-Triton X-100 buffer and centrifuged on a linear sucrose gradient extending from 1.3 M to 1.5 M with a 2.6 M cushion, at 41000 rpm for 90 min. The only apparent contaminants in the nucleolar preparation are outer cyst walls. A procedure is described for the isolation of chemically pure outer cyst walls, and a comparison of the proteins with the nucleolar preparation reveals that outer cyst walls represent negligible contaminants. The ultrastructure of these isolated nucleoli examined with transmission electron microscopy is found to be identical with that of nucleoli from whole cells, fixed in an identical manner. The 50 nucleolar proteins separated by SDS gel electrophoresis have been examined throughout the growth cycle of Acanthamoeba and into the strat of induced encystment, at which time 10 protein bands disappear, 11 bands are observed to decrease, and 8 are seen to increase in concentration. Phenol-soluble proteins are extracted from the nucleolus which correspond to 29 of the 50 nucleolar proteins, with 17 of these proteins corresponding to nucleolar proteins that change at the onset of encystment. Thes nucleolar proteins are also compared with those of rat liver nucleoli by gel electrophoresis, resulting in the observation that extremely few protein homologies exist between the two. Numerous quantitative and qualitative changes in the gel pattern of phenol-soluble nuclear proteins during early and late log phase growth and the onset of stationary phase were also observed.

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