Amino Acid Activation and Transfer to Ribonucleic Acids in the Cell Nucleus

Hopkins, J. W.

doi:10.1073/pnas.45.10.1461

Cited by 49 publications

(15 citation statements)

References 27 publications

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“…It was mentioned earlier that previous work on amino acid uptake by isolated thymus nuclei had made it exceedingly probable that free nuclei can synthesize protein autonomously, and that they utilize a biosynthetic pathway resembling that of the cytoplasm; i.e., amino acid activation by ATP (38,39), amino acid transfer to lowmolecular-weight RNA's (38-39) and formation of peptide bonds on intranuclear ribosomal particles (31,7). Among the experimental facts supporting this conclusion, the following are especially significant:…”

Section: Discussionmentioning

confidence: 99%

“…(1) Amino acid-activating enzymes have been localized in thymus nuclei and in other nuclear preparations of high purity (38,42). Since the nuclei were prepared from different tissues in non-aqueous media as well as in isotonic and hypertonic sucrose solutions (38), the intranuclear localization of the enzymes seems certain.…”

Section: Discussionmentioning

confidence: 99%

“…Since the nuclei were prepared from different tissues in non-aqueous media as well as in isotonic and hypertonic sucrose solutions (38), the intranuclear localization of the enzymes seems certain.…”

Section: Discussionmentioning

confidence: 99%

“…In previous work on amino acid uptake by isolated thymus nuclei in vitro, many different types of evidence were presented to show that nuclei can, in fact, synthesize protein autonomously, and that they utilize a biosynthetic pathway involving amino acid activation by ATP (38,39), amino acid transfer to low-molecularweight RNAs (38,39), and peptide bond formation on ribonucleoprotein particles ("nuclear ribosomes") (31, 7). Much of this evidence is assembled and summarized in the Discussion.…”

Section: Evidence For Nuclear Protein Synthesis In Vitromentioning

confidence: 99%

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Methods for the Purification of Thymus Nuclei and Their Application to Studies of Nuclear Protein Synthesis

Allfrey

Littau

Mirsky

1964

The Journal of Cell Biology

172

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Procedures are described for the purification of calf thymus nuclei using mild hypotonit shock to break intact cells, and layering techniques to remove cytoplasmic debris. Ficolc (a high polymer of sucrose) was dissolved in isotonic sucrose to give dense solutions suitable for gradient centrifugation. The method yields nuclei which can incorporate amino acids in vitro. Thymus nuclei isolated under isotonic conditions were incubated with C14-amino acids and later purified by centrifugation through dense sucrose solutions. The distribution of radioactivity in different nuclear proteins was measured and it was found that isotopic amino acids are actively incorporated into characteristically chromosomal proteins, such as the arginine-rich and lysine-rich histones. Protein synthesis in the nucleus is markedly inhibited by puromycin and by agents, such as 2,4-dinitrophenol, which inhibit ATP synthesis. The synthesis of histones is also inhibited by puromycin, but the uptake of several amino acids into the lysine-rich histone fraction seems less sensitive to puromycin inhibition than is uptake into the arginine-rich histones or other proteins of the nucleus. High resolution autoradiography using tritiated leucine and observing grain distribution over thin sections of isolated nuclei and whole cells shows that amino acid incorporation occurs within the nucleus and is not due to cytoplasmic contamination.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Evidence For Nuclear Protein Synthesis In Vitromentioning

confidence: 99%

See 2 more Smart Citations

Methods for the Purification of Thymus Nuclei and Their Application to Studies of Nuclear Protein Synthesis

Allfrey

Littau

Mirsky

1964

The Journal of Cell Biology

172

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“…Moreover, it appears that priming is more sensitive to chloramphenicol than is the induction of a secondary response (1). Indeed, bacteria and the cell-free systems derived from them require ranges from 10 to 50 ttg/ml for inhibition (15)(16)(17)(18) more like the secondary response in tissue culture.…”

Section: Discussionmentioning

confidence: 99%

Studies on Antibody Production

Cruchaud

Coons

1964

The Journal of Experimental Medicine

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The preceding paper describes the inhibition by chloramphenicol of "priming" for the secondary antibody response by a standard dose of antigen (1). For full effect, the inhibiting drug must have been administered from the day of stimulus continuously for 10 to 14 days thereafter. This paper examines this phenomenon in more detail; the results confirm the earlier experiments and indicate that priming can be effected within 3 hours after a subcutaneous injection of antigen.Little work has been done until recently on the effect of chloramphenicol on antibody formation. Slanetz (2) reported a decrease in the agglutinin response in rats to Salmonella enteritidis when they were fed chloramphenicol 1 for long periods. But neither Watson (3), nor Zhuravleva and Gorchakova (4) could demonstrate such an effect in rabbits given bacterial antigens and chloramphenicol in doses of 20 to 55 mg/kg/day. And Nathan eb al. (5) also failed to demonstrate impairment of the agglutinin response to sheep erythrocytes in mice given 250 mg/kg/day. These contraAictory findings were resolved, in part, when Ambrose and Coons (6) recently reported that chloramphenicol in bactericidal concentrations completely inhibited the secondary antibody response in tissue culture. They found that its inhibitory action was effective only during the first stages of the response, before the synthesis of antibody was well under way, and that it was without effect later, during the period when most of the antibody was produced. This led them to suggest that chloramphenicol interferes with messenger RNA, and that the apparent insensitivity of mammalian systems was due to the greater stability of mammalian messenger. In line with this suggestion was the report by Weisberger et al. (7), working also with a mammalian system, reticulocyte ribosomes. They found that chloramphenicol in a concen-

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Biochemie der Zellstrukturen

Siebert

1968

Stoffwechsel Und Feinstruktur Der Zelle I

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Amino Acid Activation and Transfer to Ribonucleic Acids in the Cell Nucleus

Cited by 49 publications

References 27 publications

Methods for the Purification of Thymus Nuclei and Their Application to Studies of Nuclear Protein Synthesis

Methods for the Purification of Thymus Nuclei and Their Application to Studies of Nuclear Protein Synthesis

Studies on Antibody Production

Biochemie der Zellstrukturen

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