Control of protein synthesis during the activation of lymphocytes by phytohaemagglutinin

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Abstract

During the activation of lymphocytes by phytohaemagglutinin the rate of synthesis of proteins increases markedly. This is accompanied by a large increase in the rate of synthesis of ribosomal RNA but the increase in the total numbers of ribosomes is less dramatic. Calculation of the average rate of protein synthesis per ribosome in lymphocyte cultures at different stages of activation showed that this rate increased considerably during activation, especially in the period preceeding the initiation of DNA synthesis.

The percentage of lymphocyte ribosomes active in protein synthesis has been determined by their resistance to dissociation to subunits at high ionic strength. More than 70 % of the ribosomes of resting lymphocytes were inactive at any instant as judged by this criterion. This proportion decreases to about 30 % during the pre-DNA synthetic stage of lymphocyte stimulation, and remains low throughout the S period. Activation of inactive ribosomes accounts for much of the increase in the average rate of protein synthesis per ribosome seen during the early period of activation, but at later stages there must also be an increase in the average rate of protein synthesis per active ribosome. Ribosomes synthesized before and after addition of phytohaemagglutinin to lymphocytes are equally active.

Investigation of the properties of the inactive ribosomes of resting lymphocytes has shown that, unlike those of stimulated cells, they do not become attached to polyribosomes when protein synthesis is partially inhibited by cycloheximide. They are, however, capable of attaching to the synthetic messenger RNA poly(U).

References (42)

  • J.E. Kay

    Exp. Cell Res.

    (1969)
  • D. Killander et al.

    Exp. Cell Res.

    (1965)
  • R. Rigler et al.

    Exp. Cell Res.

    (1969)
  • A. Zetterberg et al.

    Exp. Cell Res.

    (1969)
  • Z. Darzynkiewicz et al.

    Exp. Cell Res.

    (1969)
  • H.L. Cooper

    J. Biol. Chem.

    (1969)
  • J.E. Kay et al.

    Biochim. Biophys. Acta

    (1969)
  • T.E. Martin et al.

    J. Mol. Biol.

    (1969)
  • G.R. Lawford

    Biochem. Biophys. Res. Commun.

    (1969)
  • E.A. Zylber et al.

    Biochem. Biophys. Acta

    (1970)
  • T.E. Martin et al.

    J. Biol. Chem.

    (1970)
  • H.L. Cooper

    J. Biol. Chem.

    (1968)
  • W. McCormick et al.

    J. Mol. Biol.

    (1969)
  • C.P. Stanners

    Biochem. Biophys. Res. Commun.

    (1966)
  • B.L.M. Hogan

    Biochim. Biophys. Acta

    (1969)
  • J.E. Kay et al.

    Exp. Cell Res.

    (1969)
  • A.D. Rubin

    Blood

    (1970)
  • H. Fan et al.

    J. Mol. Biol.

    (1970)
  • S.Y. Lin et al.

    J. Mol. Biol.

    (1966)
  • W. Gilbert

    J. Mol. Biol.

    (1963)
  • P.C. Nowell

    Cancer Res.

    (1960)
  • Cited by (0)

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