PMID: 5920197Apr 1, 1966

The in vivo protein synthetic activities of free versus membrane-bound ribonucleoprotein in a plasma-cell tumor of the mouse

The Journal of Cell Biology
E L KuffN E Roberts

Abstract

Cytoplasmic extracts of the transplantable RPC-20 plasma-cell tumor were fractionated by sucrose density gradient centrifugation. Four major fractions were distinguished: (a) microsomes and mitochondria; (b) membrane-free polyribosomes; (c) free monomeric ribosomes; and (d) soluble fraction. The fractions were analyzed for RNA and lipid phosphorus, and their particulate components were characterized by electron microscopy. Particular attention was paid to the problem of membrane contamination of the free polyribosome fraction. It was shown that this contamination was small in relation with the total content of ribosomes in the fraction, and that it consisted primarily of smooth-surfaced membranes which were not physically associated with the polyribosomes themselves. In vivo incorporation studies were carried out by injecting tumor-bearing animals intravenously with leucine-C(14), removing the tumors at various times thereafter, and determining the distribution of protein radioactivity among the gradient-separated cytoplasmic fractions. The free polyribosome and the microsome-mitochondria fractions constituted active centers for protein synthesis. It was shown that nascent protein of the free polyribosome fractions was not asso...Continue Reading

References

Jul 15, 1965·Biochimica Et Biophysica Acta·L D Moore, W W Umbreit
Jun 9, 1965·Biochemical and Biophysical Research Communications·K Tsukada, I Lieberman
Feb 1, 1961·The Journal of Biophysical and Biochemical Cytology·J H LUFT
Nov 1, 1960·Biochemical and Biophysical Research Communications·R J MANS, G D NOVELLI
Jan 15, 1963·Proceedings of the National Academy of Sciences of the United States of America·J R WARNERA Rich
Aug 1, 1963·Journal of Molecular Biology·E C HENSHAWH H HIATT
Nov 1, 1963·Journal of Molecular Biology·D SCHLESSINGER
Sep 1, 1964·The Journal of Cell Biology·R A RIFKINDP A MARKS
Jun 1, 1960·The Journal of Biophysical and Biochemical Cytology·E L Kuff, R F ZEIGEL

Citations

Dec 22, 1969·Archiv für klinische und experimentelle Ohren- Nasen- und Kehlkopfheilkunde·H Stupp
Nov 1, 1968·The Journal of protozoology·J Sommerville, R Sinden
May 28, 1967·Journal of Molecular Biology·B Goldberg, H Green
Oct 12, 2012·Environmental Science and Pollution Research International·Khalid HabibTasneem Fatma

Related Concepts

Electron Microscopy
Neoplasm Proteins
Neoplasm Transplantation
Neoplasms, Experimental
Nucleoproteins
Plasmacytoma
Ribosomes
Ultracentrifugation

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