Premium
Identification and regulation of high light‐induced genes in Chlamydomonas reinhardtii
Author(s) -
Im Chung Soon,
Grossman Arthur R.
Publication year - 2002
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.2001.01287.x
Subject(s) - chlamydomonas reinhardtii , dcmu , biology , gene , chlamydomonas , carbonic anhydrase , photosystem i , chloroplast , photosystem ii , gene expression , photosynthesis , biochemistry , microbiology and biotechnology , mutant , enzyme
Summary We have used restriction fragment differential display for isolating genes of the unicellular green alga Chlamydomonas reinhardtii that exhibit elevated expression on exposure of cells to high light. Some of the high light‐activated genes were also controlled by CO 2 concentration. Genes requiring both elevated light and low CO 2 levels for activation encoded both novel polypeptides and those that function in concentrating inorganic carbon (extracellular carbonic anhydrase, low CO 2 ‐induced protein, ABC transporter of the MRP subfamily). All the genes in this category were shown to be under the control of Cia5, a protein that regulates the responses of C. reinhardtii to low‐CO 2 conditions. Genes specifically activated by high light, even under high‐CO 2 conditions, encoded a 30 kDa chloroplast membrane protein, a serine hydroxymethyltransferase, a nuclease, and two proteins of unknown function. Experiments using DCMU, an inhibitor of photosynthetic electron transport, and mutants devoid of either photosystem I or photosystem II activity, showed aberrant expression of all the genes regulated by both CO 2 and high light, suggesting that redox plays a role in controlling their expression. In contrast, there was little effect of DCMU or lesions that block photosynthetic electron transport on the activity of genes that were specifically controlled by high light.