Z-membranes: artificial organelles for overexpressing recombinant integral membrane proteins

Proc Natl Acad Sci U S A. 1996 Mar 5;93(5):2219-23. doi: 10.1073/pnas.93.5.2219.

Abstract

We have expressed a fusion protein formed between the avian infectious bronchitis virus M protein and the bacterial enzyme beta-glucuronidase in transgenic tobacco cells. Electron microscope images of such cells demonstrate that overexpression of this fusion protein gives rise to a type of endoplasmic reticulum membrane domain in which adjacent membranes become zippered together apparently as a consequence of the oligomerizing action of beta-glucuronidase. These zippered (Z-) membranes lack markers of the endoplasmic reticulum (NADH cytochrome c reductase and ribosomes) and accumulate in the cells in the form of multilayered scroll-like structures (up to 2 micrometers in diameter; 20-50 per cell) without affecting plant growth. The discovery of Z-membranes has broad implications for biology and biotechnology in that they provide a means for accumulating large quantities of recombinant membrane proteins within discrete domains of native membranes.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Base Sequence
  • Cell-Free System
  • DNA Primers / chemistry
  • Fluorescent Antibody Technique, Indirect
  • Genes, Viral
  • Glucuronidase / chemistry*
  • Infectious bronchitis virus / genetics
  • Intracellular Membranes / ultrastructure*
  • Membrane Proteins / chemistry*
  • Microscopy, Electron
  • Molecular Sequence Data
  • Nicotiana
  • Organelles / ultrastructure*
  • Plants, Genetically Modified
  • Plants, Toxic
  • Recombinant Proteins / chemistry
  • Viral Matrix Proteins / genetics
  • Viral Structural Proteins / genetics

Substances

  • DNA Primers
  • Membrane Proteins
  • Recombinant Proteins
  • Viral Matrix Proteins
  • Viral Structural Proteins
  • Glucuronidase