Photocontrol of subcellular partitioning of phytochrome-B:GFP fusion protein in tobacco seedlings

Plant J. 2000 Apr;22(2):135-45. doi: 10.1046/j.1365-313x.2000.00730.x.


Photomorphogenesis of higher plants is regulated by photoreceptors including the red/far-red light-absorbing phytochromes, blue-UV/A sensing cryptochromes and as yet uncharacterized UV/B receptors. Specific phototransduction pathways that are controlled by either individual or interacting photoreceptors mediate regulation. Phytochrome B (phyB) is the major red light-sensing photoreceptor. Phototransduction mediated by this light sensor has been shown to include light-dependent nuclear import and interaction of phyB with transcription factor-like proteins in the nucleus. Here we report that nuclear import of phyB and physiological responses regulated by this photoreceptor exhibit very similar wavelength- and fluence rate-dependence. Nuclear import of phyB is insensitive to single red, blue and far-red light pulses. It is induced by continuous red light and to a lesser extent by continuous blue light, whereas far-red light is completely ineffective. The data presented indicate that light-dependent partitioning of phyB exhibits features characteristic of blue light responsiveness amplification, a phenomenon that is thought to be mediated by interaction of phyB with CRY1.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Compartmentation
  • Cell Nucleus / metabolism*
  • Cell Nucleus / physiology
  • Green Fluorescent Proteins
  • Light*
  • Luminescent Proteins / genetics
  • Microscopy, Fluorescence
  • Photoreceptor Cells*
  • Phytochrome / genetics
  • Phytochrome / metabolism*
  • Phytochrome / physiology
  • Phytochrome B
  • Plants
  • Plants, Genetically Modified / metabolism
  • Plants, Genetically Modified / physiology
  • Plants, Toxic*
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism*
  • Recombinant Fusion Proteins / physiology
  • Subcellular Fractions / metabolism
  • Tobacco / metabolism
  • Tobacco / physiology*
  • Transcription Factors*


  • Luminescent Proteins
  • Recombinant Fusion Proteins
  • Transcription Factors
  • Phytochrome
  • Phytochrome B
  • Green Fluorescent Proteins