The PSBP2 protein of Chlamydomonas reinhardtii is required for singlet oxygen-dependent signaling

Planta. 2012 Oct;236(4):1289-303. doi: 10.1007/s00425-012-1683-1. Epub 2012 Jun 21.

Abstract

In the green alga Chlamydomonas reinhardtii, the cytosolic Glutathione Peroxidase 5 gene (GPX5) is known to be transcriptionally up-regulated in response to singlet oxygen ((1)O(2)). As demonstrated by previous studies, fusion of the promoter region of GPX5 to the Arylsulfatase 2 gene (ARS2) creates an effective reporter system that can be used to monitor (1)O(2)-driven GPX5 expression. This system was also used in this study to generate a stably transformed C. reinhardtii strain which expresses ARS2 in a (1)O(2)-dependent manner, resulting in the synthesis of a functional protein with detectable activity. Using the strain of C. reinhardtii harboring a (1)O(2)-sensitive reporter construct, a secondary mutagenic screen was performed. This allowed identification of mutant cell lines that were unable to up-regulate expression of the GPX5-ARS2 fusion in response to (1)O(2). In one of these lines, the mutation was subsequently localized to the first exon of the PSBP-like gene (PSBP2). The PSBP2 gene is part of a small protein family in C. reinhardtii, also present in all angiosperms studied thus far. While each member of the PSBP protein family contains a similar domain to the PSBP1 protein, which is a member of the oxygen evolving complex of photosystem II (PSII), the PSBP2 protein does not appear to be involved in PSII function, but may function as a sensor and/or signal mediating molecule of the (1)O(2) generated in the chloroplast.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptation, Physiological*
  • Arylsulfatases / genetics
  • Arylsulfatases / metabolism
  • Chlamydomonas reinhardtii / drug effects*
  • Chlamydomonas reinhardtii / genetics*
  • Chlamydomonas reinhardtii / physiology
  • Chlamydomonas reinhardtii / radiation effects
  • Chlorophyll / metabolism
  • Chloroplasts / drug effects
  • Chloroplasts / genetics
  • Chloroplasts / physiology
  • Chloroplasts / radiation effects
  • Gene Expression Regulation, Enzymologic
  • Gene Expression Regulation, Plant
  • Genetic Complementation Test
  • Glutathione Peroxidase / genetics
  • Glutathione Peroxidase / metabolism
  • Light
  • Mutation
  • Oxidative Stress
  • Oxygen / metabolism
  • Photosynthesis
  • Phylogeny
  • Plant Proteins / drug effects
  • Plant Proteins / genetics
  • Plant Proteins / metabolism
  • Protein Structure, Tertiary
  • RNA, Plant / genetics
  • Signal Transduction / drug effects*
  • Singlet Oxygen / pharmacology*
  • Up-Regulation

Substances

  • Plant Proteins
  • RNA, Plant
  • Chlorophyll
  • Singlet Oxygen
  • Glutathione Peroxidase
  • selenium-independent glutathione peroxidase
  • Arylsulfatases
  • Oxygen