Induction of a rapidly responsive hepatic gene product by thyroid hormone requires ongoing protein synthesis.

The regulation of a gene, designated spot 14, which is rapidly induced in rat liver in response to 3,5,3'-triiodo-L-thyronine (T3) was studied as a model for exploring the molecular basis of thyroid hormone action. The time course of induction of the nuclear precursor to spot 14 mRNA after intramuscular injection of T3 displayed a very short lag period of between 10 and 20 min. The rapidity of this effect suggests that the induction in gene expression occurs as a primary response to the hormone-receptor interaction. The protein synthesis inhibitor cycloheximide injected 15 min before T3 completely blocked the accumulation of nuclear precursor RNA 30 min after T3 treatment. Emetine, an inhibitor of protein synthesis which acts by a different mechanism than cycloheximide, also blocked the induction of the spot 14 nuclear precursor RNA. The increased rate of spot 14 gene transcription observed after T3 treatment, as measured by nuclear run-on assay, was similarly completely abolished in the presence of cycloheximide. In addition, ongoing protein synthesis was required for maintaining spot 14 nuclear precursor RNA at induced levels in animals previously treated with T3. On the other hand, cycloheximide had no effect on T3 uptake or binding to the nuclear receptor during the 45-min time frame studied. The paradox of the rapid kinetics of induction and the requirement of ongoing protein synthesis may be explained by a protein with an extremely short half-life which is necessary for T3 induction of the spot 14 gene.

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Inhibitor of protein synthesis phase shifts a circadian pacemaker in mammalian SCN

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1988.255.6.r1055 ◽

1988 ◽

Vol 255 (6) ◽

pp. R1055-R1058

Author(s):

S. T. Inouye ◽

J. S. Takahashi ◽

F. Wollnik ◽

F. W. Turek

Keyword(s):

Protein Synthesis ◽

Circadian Rhythms ◽

Activity Rhythm ◽

Phase Shifts ◽

Protein Synthesis Inhibitor ◽

Circadian Pacemaker ◽

Synthesis Inhibitor ◽

Anatomic Site ◽

Site Of Action ◽

Inhibitor Of Protein Synthesis

The suprachiasmatic nucleus (SCN) of the hypothalamus contains a circadian pacemaker that regulates many circadian rhythms in mammals. Experimental work in microorganisms and invertebrates suggests that protein synthesis is required for the function of the circadian oscillator, and recent experiments in golden hamsters suggest an acute inhibition of protein synthesis can induce phase shifts in a mammalian circadian pacemaker. To determine whether protein synthesis in the SCN region is involved in the generation of circadian rhythms in mammals, a protein synthesis inhibitor, anisomycin, was microinjected into the SCN region, and the effect on the circadian rhythm of locomotor activity of hamsters was measured. A single injection of anisomycin into the SCN region induced phase shifts in the circadian activity rhythm that varied systematically as a function of the phase of injection within the circadian cycle. These results suggest that protein synthesis may be involved in the generation of circadian rhythms in mammals and that the anatomic site of action of anisomycin is within the hypothalamic suprachiasmatic region.

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Different Training Procedures Recruit Either One or Two Critical Periods for Contextual Memory Consolidation, Each of Which Requires Protein Synthesis and PKA

Learning & Memory ◽

10.1101/lm.5.4.365 ◽

1998 ◽

Vol 5 (4) ◽

pp. 365-374 ◽

Cited By ~ 23

Author(s):

Roussoudan Bourtchouladze ◽

Ted Abel ◽

Nathaniel Berman ◽

Rachael Gordon ◽

Kyle Lapidus ◽

...

Keyword(s):

Protein Synthesis ◽

Time Course ◽

Contextual Fear Conditioning ◽

Long Term Memory ◽

Protein Synthesis Inhibitor ◽

Critical Periods ◽

Synthesis Inhibitor ◽

Contextual Memory ◽

Contextual Fear

We have used a combined genetic and pharmacological approach to define the time course of the requirement for protein kinase A (PKA) and protein synthesis in long-term memory for contextual fear conditioning in mice. The time course of amnesia in transgenic mice that express R(AB) and have genetically reduced PKA activity in the hippocampus parallels that observed both in mice treated with inhibitors of PKA and mice treated with inhibitors of protein synthesis. This PKA- and protein synthesis-dependent memory develops between 1 hr and 3 hr after training. By injecting the protein synthesis inhibitor anisomycin or the PKA inhibitor Rp-cAMPs at various times after training, we find that depending on the nature of training, contextual memory has either one or two brief consolidation periods requiring synthesis of new proteins, and each of these also requires PKA. Weak training shows two time periods of sensitivity to inhibitors of protein synthesis and PKA, whereas stronger training exhibits only one. These studies underscore the parallel dependence of long-term contextual memory on protein synthesis and PKA and suggest that different training protocols may recruit a common signaling pathway in distinct ways.

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Genetic and biochemical distinction among Chinese hamster cell emtA, emtB, and emtC mutants

Molecular and Cellular Biology ◽

10.1128/mcb.3.3.429-438.1983 ◽

1983 ◽

Vol 3 (3) ◽

pp. 429-438

Author(s):

S Chang ◽

J J Wasmuth

Keyword(s):

Protein Synthesis ◽

Ribosomal Protein ◽

Ribosomal Proteins ◽

Chinese Hamster ◽

Cross Resistance ◽

Protein Synthesis Inhibitor ◽

Chromosome 2 ◽

Synthesis Inhibitor ◽

Chinese Hamster Cells ◽

Inhibitor Of Protein Synthesis

Genetic and biochemical experiments have enabled us to more clearly distinguish three genetic loci, emtA, emtB, and emtC, all of which can be altered to give rise to resistance to the protein synthesis inhibitor, emetine, in cultured Chinese hamster cells. Genetic experiments have demonstrated that, unlike the emtB locus, neither the emtA locus nor the emtC locus is linked to chromosome 2 in Chinese hamster cells, clearly distinguishing the latter two genes from emtB. emtA mutants can also be distinguished, biochemically, from emtB and emtC mutants based upon different degrees of cross-resistance to another inhibitor of protein synthesis, cryptopleurine. Two-dimensional gel electrophoretic analysis of ribosomal proteins failed to detect any electrophoretic alterations in ribosomal proteins from emtA or emtC mutants that could be correlated with emetine resistance. However, a distinct electrophoretic alteration in ribosomal protein S14 was observed in an emtB mutant. In addition, the parental Chinese hamster peritoneal cell line of an emtC mutant, and the emtC mutant itself, are apparently heterozygous for an electrophoretic alteration in ribosomal protein L9.

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Genetic and biochemical distinction among Chinese hamster cell emtA, emtB, and emtC mutants.

Molecular and Cellular Biology ◽

10.1128/mcb.3.3.429 ◽

1983 ◽

Vol 3 (3) ◽

pp. 429-438 ◽

Cited By ~ 4

Author(s):

S Chang ◽

J J Wasmuth

Keyword(s):

Protein Synthesis ◽

Ribosomal Protein ◽

Ribosomal Proteins ◽

Chinese Hamster ◽

Cross Resistance ◽

Protein Synthesis Inhibitor ◽

Chromosome 2 ◽

Synthesis Inhibitor ◽

Chinese Hamster Cells ◽

Inhibitor Of Protein Synthesis

Genetic and biochemical experiments have enabled us to more clearly distinguish three genetic loci, emtA, emtB, and emtC, all of which can be altered to give rise to resistance to the protein synthesis inhibitor, emetine, in cultured Chinese hamster cells. Genetic experiments have demonstrated that, unlike the emtB locus, neither the emtA locus nor the emtC locus is linked to chromosome 2 in Chinese hamster cells, clearly distinguishing the latter two genes from emtB. emtA mutants can also be distinguished, biochemically, from emtB and emtC mutants based upon different degrees of cross-resistance to another inhibitor of protein synthesis, cryptopleurine. Two-dimensional gel electrophoretic analysis of ribosomal proteins failed to detect any electrophoretic alterations in ribosomal proteins from emtA or emtC mutants that could be correlated with emetine resistance. However, a distinct electrophoretic alteration in ribosomal protein S14 was observed in an emtB mutant. In addition, the parental Chinese hamster peritoneal cell line of an emtC mutant, and the emtC mutant itself, are apparently heterozygous for an electrophoretic alteration in ribosomal protein L9.

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Isolation and partial characterization of a protein synthesis inhibitor from brine shrimp embryos

Canadian Journal of Biochemistry ◽

10.1139/o77-144 ◽

1977 ◽

Vol 55 (9) ◽

pp. 965-974 ◽

Cited By ~ 7

Author(s):

A. H. Warner ◽

V. Shridhar ◽

F. J. Finamore

Keyword(s):

Protein Synthesis ◽

Translational Control ◽

Brine Shrimp ◽

Elongation Factor ◽

Artemia Salina ◽

Protein Synthesis Inhibitor ◽

Synthesis Inhibitor ◽

Elongation Step ◽

Artemia Cysts ◽

Inhibitor Of Protein Synthesis

Encysted embryos of the brine shrimp, Artemia salina, contain an inhibitor of protein synthesis that appears to be important in translational control. In cyst homogenates, the inhibitor appears to be partitioned almost equally between the cytosol and ribosome fractions and it has been purified from both fractions to near homogeneity. In a cell-free protein-synthesizing system derived from Artemia cysts, with poly(U) as messenger, the protein inhibits polyphenylalanine synthesis proportional to inhibitor concentration up to about 75% inhibition, and the primary site of action appears to be at the elongation step. The inhibitor activity is not altered by 50–150 mM KCl in the reaction mixture, but it is slightly more effective at 5 mM MgCl2 than at 10 mM MgCl2. The inhibitor is a heat-labile protein of 130 000 molecular weight and is devoid of hydrolase activity. Our data indicate that the inhibitor is not elongation factor EF-1 or EF-2, but we are studying the possibility that it may be a modified form of elongation factor EF-2.

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