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Medientyp:
E-Artikel
Titel:
Tiered Regulation of Sulfur Deprivation Responses in Chlamydomonas reinhardtii and Identification of an Associated Regulatory Factor
Beteiligte:
Aksoy, Munevver;
Pootakham, Wirulda;
Pollock, Steve V.;
Moseley, Jeffrey L.;
González-Ballester, David;
Grossman, Arthur R.
Erschienen:
Oxford University Press (OUP), 2013
Erschienen in:
Plant Physiology, 162 (2013) 1, Seite 195-211
Sprache:
Englisch
DOI:
10.1104/pp.113.214593
ISSN:
1532-2548
Entstehung:
Anmerkungen:
Beschreibung:
Abstract During sulfur (S) deprivation, the unicellular alga Chlamydomonas reinhardtii exhibits increased expression of numerous genes. These genes encode proteins associated with sulfate (SO4 2−) acquisition and assimilation, alterations in cellular metabolism, and internal S recycling. Administration of the cytoplasmic translational inhibitor cycloheximide prevents S deprivation-triggered accumulation of transcripts encoding arylsulfatases (ARS), an extracellular polypeptide that may be important for cell wall biosynthesis (ECP76), a light-harvesting protein (LHCBM9), the selenium-binding protein, and the haloperoxidase (HAP2). In contrast, the rapid accumulation of transcripts encoding high-affinity SO4 2− transporters is not affected. These results suggest that there are two tiers of transcriptional regulation associated with S deprivation responses: the first is protein synthesis independent, while the second requires de novo protein synthesis. A mutant designated ars73a exhibited low ARS activity and failed to show increases in ECP76, LHCBM9, and HAP2 transcripts (among others) in response to S deprivation; increases in transcripts encoding the SO4 2− transporters were not affected. These results suggest that the ARS73a protein, which has no known activity but might be a transcriptional regulator, is required for the expression of genes associated with the second tier of transcriptional regulation. Analysis of the ars73a strain has helped us generate a model that incorporates a number of complexities associated with S deprivation responses in C. reinhardtii.