Molecular Genetics and Genomics

, Volume 266, Issue 3, pp 363–373

Characterization of Chlamydomonas mutants defective in the H subunit of Mg-chelatase

  •  E. Chekounova
  •  V. Voronetskaya
  •  J. Papenbrock
  •  B. Grimm
  •  C. Beck
Original Paper

Abstract.

Two chlorophyll-deficient mutants of Chlamydomonas reinhardtii, chl1 and brs-1, are light sensitive and, when grown heterotrophically in the dark, accumulate protoporphyrin IX and exhibit yellow/orange pigmentation. The lesions in both mutants were mapped to the gene (CHLH) for the plastid-localized H subunit of the heterotrimeric magnesium chelatase that catalyzes the insertion of magnesium into protoporphyrin IX. The genetic defects in the mutants could be assigned to +1 frameshift mutations in exon 9 (chl1) and exon 10 (brs-1) of the CHLH gene. In both mutants, the H subunit of magnesium chelatase was undetectable, but, as shown for chl1, the steady-state levels of the I and D subunits were unaltered in comparison to wild type. The CHLH gene exhibits marked light inducibility: levels of both the mRNA and the protein product are strongly increased when cultures are shifted from from the dark into the light, suggesting that this protein may play a crucial role in the light regulation of chlorophyll biosynthesis.

Chlamydomonas CHLH gene Mg-chelatase Mutants Protoporphyrin IX 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Copyright information

© Springer-Verlag 2001

Authors and Affiliations

  •  E. Chekounova
    • 1
  •  V. Voronetskaya
    • 2
  •  J. Papenbrock
    • 2
  •  B. Grimm
    • 2
  •  C. Beck
    • 1
  1. 1.Institut für Biologie III, Universität Freiburg, Schänzlestrasse 1, 79104 Freiburg, Germany
  2. 2.Institut für Pflanzengenetik und Kulturpflanzenforschung, Corrensstrasse 3, 06466 Gatersleben, Germany
  3. 3.Permanent address: Biological Institute, St. Petersburg State University, Oranienbaum Chaussee 2, Stary Peterhof, 198504 St. Petersburg, Russia
  4. 4.Present address: Botanisches Institut, Universität Hannover, Herrenhäuserstrasse 2, 30419 Hannover, Germany
  5. 5.Present address: Institut für Biologie/Pflanzenphysiologie, Humboldt Universität, Unter den Linden 6, 10099 Berlin, Germany

Personalised recommendations