REGULATION OF THE INITIATION OF HEMOGLOBIN SYNTHESIS IN THE BLOOD ISLAND CELLS OF CHICK EMBRYOS. IV. EFFECTS OF SOME INHIBITORS OF PROTEIN SYNTHESIS

1967 ◽  
Vol 45 (10) ◽  
pp. 1648-1651
Author(s):  
S. D. Wainwright ◽  
Lillian K. Wainwright
Keyword(s):  
Protein Synthesis ◽  
Chick Embryos ◽  
Hemoglobin Synthesis ◽  
Blood Island

REGULATION OF THE INITIATION OF HEMOGLOBIN SYNTHESIS IN THE BLOOD ISLAND CELLS OF CHICK EMBRYOS: V. QUALITATIVE STUDIES OF THE EFFECTS OF PROFLAVINE

1967 ◽  
Vol 45 (10) ◽  
pp. 1483-1493 ◽  
Author(s):  
S. D. Wainwright ◽  
Lillian K. Wainwright
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Developmental Stages ◽  
Low Molecular Weight ◽  
Chick Embryos ◽  
Hemoglobin Synthesis ◽  
Blood Island ◽  
Naked Eye ◽  
Stage Of Development ◽  
Eye Formation

Most blastodiscs explanted before the 1-somite stage of development onto medium containing 20 μg of proflavine/ml failed to form any detectable hemoglobin, whereas the majority explanted at later stages formed hemoglobin visible to the naked eye. Formation of hemoglobin by 2-somite blastodiscs was suppressed by proflavine at 50 μg/ml, but 6-somite blastodiscs formed visible quantities of hemoglobin. Incorporation of leucine into protein was inhibited by proflavine, and almost the same amount of inhibition was produced at both concentrations of inhibitor for all developmental stages examined.Net incorporation of uridine into acid-precipitable material was moderately inhibited by 20 μg of proflavine/ml, and almost totally suppressed by 50 μg of proflavine/ml. Only polynucleotides of low molecular weight accumulated in blastodiscs treated with either concentration of proflavine, but preformed stable RNA's were not degraded in the presence of inhibitor. Proflavine appeared to inhibit synthesis of, or cause degradation of, new RNA of high molecular weight at both concentrations. Accumulation of RNA of low molecular weight continued at a low proflavine concentration, but little additional RNA accumulated at a high proflavine concentration.

scholarly journals Precommitted erythroid cells enriched in cultures of suboptimally induced Friend erythroleukemia cells

Blood ◽  
1987 ◽  
Vol 70 (5) ◽  
pp. 1565-1571
Author(s):  
E DiMambro ◽  
M Galanti ◽  
SB Levy
Keyword(s):  
Protein Synthesis ◽  
Rna Synthesis ◽  
Terminal Differentiation ◽  
Metabolic Inhibitors ◽  
Hemoglobin Synthesis ◽  
Erythroleukemia Cells ◽  
Chemically Induced ◽  
Primed Cell ◽  
Murine Erythroleukemia ◽  
New Protein

Abstract In the presence of suboptimal inducing amounts of dimethylsulfoxide or hexamethylenebisacetamide, a major proportion of uncommitted murine erythroleukemia (MEL) cells was found to be precommitted or primed for commitment, which was demonstrated by their rapid commitment to terminal differentiation when recultured for short periods of time (three to six hours) with fresh inducer. These same cells did not commit if left in the original inducer-containing media or if replated in fresh media without inducer. The two inducers could be interchanged in the priming and postpriming period without affecting the commitment event. However, hemin, an agent that induces hemoglobin synthesis without commitment, showed no ability to enhance commitment of a primed cell population. The rapid commitment of primed cells was inhibited by 12-O-tetradecanoylphorbol-13-acetate and cordycepin but not by cycloheximide. The latter finding indicated that this rapid inducer- dependent commitment event required new RNA synthesis but not new protein synthesis. The precommitment state was lost within six hours of the growth of cells in the absence of inducer but could be sustained longer if cells were incubated in cycloheximide. These studies characterize a precommitment state not previously described and one that appears during chemically induced differentiation in the absence of metabolic inhibitors. The stabilization of these precommitted cells by cycloheximide suggests that the reversibility of precommitment involves new protein synthesis. These findings show that MEL cells proceed to terminal differentiation by accumulating unstable products that must be maintained by the inducer until the final commitment event.

Comparison of the Transfer RNA Complements of Chick Embryos and their Supporting Membranes

1972 ◽  
Vol 50 (10) ◽  
pp. 1056-1063 ◽  
Author(s):  
S. D. Wainwright ◽  
Julia C. Thompson ◽  
J. F. Prchal ◽  
H. M. Tsay
Keyword(s):  
Minor Component ◽  
Transfer Rna ◽  
Quantitative Change ◽  
Chick Embryos ◽  
Hemoglobin Synthesis ◽  
Distribution Of Components

The transfer RNA complement of 5- to 6-day chick embryos was compared with that of the associated membranes by chromatography of preparations of aminoacyl-tRNAs on columns of benzoylated diethyl-aminoethylcellulose. Profiles of all aminoacyl-tRNAs were determined under conditions selected for emphasis on the region containing a component believed to play a role in regulating onset of rapid hemoglobin synthesis in the blood islands of young blastodiscs. Differences in profile were observed only for alanyl- and glutamyl-tRNAs. A marked quantitative change in the distribution of components in the complement of glutamyl-tRNAs was in the converse direction of that required for increase in content of putative regulator and was not further investigated.Small reproducible differences in the profiles of alanyl-tRNAs were further investigated and were shown to be due to a marked increase in the content of a distinct minor component of the alanyl-tRNA complement of the membranes relative to that of the embryo.

REGULATION OF THE INITIATION OF HEMOGLOBIN SYNTHESIS IN THE BLOOD ISLAND CELLS OF CHICK EMBRYOS: I. QUALITATIVE STUDIES OF THE EFFECTS OF ACTINOMYCIN AND δ-AMINOLEVULINIC ACID

1966 ◽  
Vol 44 (11) ◽  
pp. 1543-1560 ◽  
Author(s):  
S. D. Wainwright ◽  
Lillian K. Wainwright
Keyword(s):  
Aminolevulinic Acid ◽  
Basal Medium ◽  
Primitive Streak ◽  
Chick Embryos ◽  
Messenger Rnas ◽  
Stages Of Development ◽  
Linear Rate ◽  
Hemoglobin Synthesis ◽  
Naked Eye ◽  
Somite Stage

Intact and de-embryonated blastodiscs of chick embryos from all stages of development between the definitive primitive streak and the 10-somite stage were incubated on simple solid synthetic media. On the basal medium, blastodiscs at all initial stages of development synthesized hemoglobin readily visible to the naked eye within 24 hours, incorporated leucine into protein at an approximately linear rate for 24 hours, and incorporated uridine into RNA at a roughly linear rate for at least 6 hours after a short lag.Blastodiscs taken before the 1-somite stage failed to synthesize any detectable hemoglobin on medium containing 2 μg/ml of actinomycin, whereas those token at later stages synthesized hemoglobin visible to the naked eye. This concentration of actinomycin totally inhibited the incorporation of uridine into high molecular weight RNA within 2–3 hours, but the incorporation of leucine into protein was not inhibited for 6–8 hours. The residual incorporation of uridine was entirely into the soluble RNA fraction.At 10 μg/ml, actinomycin markedly inhibited the synthesis of hemoglobin by blastodiscs taken at stages earlier than the 6-somite embryo, but did not markedly affect hemoglobin synthesis by the more advanced blastodiscs. This concentration of actinomycin caused only slightly greater inhibition of the incorporation of uridine into acid-precipitable material than the smaller concentration for all blastodiscs, and was not markedly more inhibitory for the incorporation of leucine into protein.The presence of δ-aminolevulinic acid overcame the inhibitions of synthesis of hemoglobin by actinomycin but did not prevent the inhibitions of incorporation of uridine into RNA and of leucine into protein.Regulation of the onset of rapid hemoglobin synthesis appears to be at the translation level, probably through the supply of δ-aminolevulinic acid. The latter is probably regulated through synthesis of RNAs formed at the head-fold stage. Messenger RNAs for globin synthesis are present at the stage of the definitive primitive streak.

scholarly journals A simple method for evaluating whole body protein synthesis in chick embryos in vivo.

1987 ◽  
Vol 24 (1) ◽  
pp. 39-43 ◽  
Author(s):  
Tatsuo MURAMATSU ◽  
Toshiyasu KATO ◽  
Jun-ichi OKUMURA ◽  
Iwao TASAKI
Keyword(s):  
Protein Synthesis ◽  
Whole Body ◽  
Chick Embryos ◽  
Simple Method ◽  
Body Protein

scholarly journals ERYTHROPOIETIC CELL CULTURES FROM CHICK EMBRYOS

1972 ◽  
Vol 54 (1) ◽  
pp. 98-106 ◽  
Author(s):  
Helen K. Hagopian ◽  
Judith A. Lippke ◽  
Vernon M. Ingram
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Cell Cultures ◽  
Morphological Changes ◽  
Chick Embryos ◽  
Red Cell ◽  
In Ovo ◽  
Hemoglobin Synthesis ◽  
Cycle Times ◽  
Cell Series

Erythropoietic cell cultures from very early chick blastoderms survive for several days They show four to seven doublings of the erythroid cells and the appropriate morphological changes from proerythroblasts to mature erythrocytes Cell cycle times are the same as in ovo for the first day of culture, but slow down thereafter The hemoglobins of both the primitive and the definitive red cell series are produced. 5-Bromodeoxyuridine added to the cultures inhibits differentiation and hemoglobin synthesis, though not cell division, but quite soon the cells cease being sensitive The effect of the drug can be reversed by the addition of thymidine.

scholarly journals ERYTHROPOIETIN EFFECTS ON FETAL MOUSE ERYTHROID CELLS

1971 ◽  
Vol 51 (3) ◽  
pp. 585-595 ◽  
Author(s):  
David H. K. Chui ◽  
Meir Djaldetti ◽  
Paul A. Marks ◽  
Richard A. Rifkind
Keyword(s):  
Protein Synthesis ◽  
Adult Mouse ◽  
Absolute Number ◽  
Precursor Cells ◽  
Erythroid Precursor ◽  
Hemoglobin Synthesis ◽  
Fetal Mouse ◽  
Globin Chains ◽  
Principal Effect ◽  
Stimulation Of

The effect of the hormone, erythropoietin, on cultures of erythroblasts derived from the livers of fetal C57BL/6J mice was examined. An increase both in the content and in the rate of synthesis of normal adult mouse globin chains was detected in hormone-treated cultures. The rate of protein synthesis by individual erythroblasts does not increase in response to the hormone, whereas the absolute number of hemoglobin-synthesizing cells does increase and accounts for the observed stimulation of hemoglobin synthesis. The principal effect of erythropoietin appears to be upon the population of immature erythroid precursor cells which persists in the presence of the hormone, the cells maintaining their ability to replicate, and their capacity to differentiate into hemoglobinizing erythroblasts. In the absence of hormone, already committed erythroblasts continue their development, but erythropoiesis is not sustained.

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