Oxygen Deficiency Responsive Gene Expression in Chlamydomonas reinhardtii through a Copper-Sensing Signal Transduction Pathway1
AUTOR(ES)
Quinn, Jeanette M.
FONTE
American Society of Plant Physiologists
RESUMO
Chlamydomonas reinhardtii activates Cpx1, Cyc6, and Crd1, encoding, respectively, coproporphyrinogen oxidase, cytochrome c6, and a novel di-iron enzyme when transferred to oxygen-deficient growth conditions. This response is physiologically relevant because C. reinhardtii experiences these growth conditions routinely, and furthermore, one of the target genes, Crd1, is functionally required for normal growth under oxygen-depleted conditions. The same genes are activated also in response to copper-deficiency through copper-response elements that function as target sites for a transcriptional activator. The core of the copper-response element, GTAC, is required also for the hypoxic response, as is a trans-acting locus, CRR1. Mercuric ions, which antagonize the copper-deficiency response, also antagonize the oxygen-deficiency response of these target genes. Taken together, these observations suggest that the oxygen- and copper-deficiency responses share signal transduction components. Nevertheless, whereas the copper-response element is sufficient for the nutritional copper response, the oxygen-deficiency response requires, in addition, a second cis-element, indicating that the response to oxygen depletion is not identical to the nutritional copper response. The distinction between the two responses is also supported by comparative analysis of the response of the target genes, Cyc6, Cpx1, and Crd1, to copper versus oxygen deficiency. A Crr1-independent pathway for Hyd1 expression in oxygen-depleted C. reinhardtii demonstrates the existence of multiple oxygen/redox-responsive circuits in this model organism.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=148909Documentos Relacionados
- Copper Response Element and Crr1-Dependent Ni2+-Responsive Promoter for Induced, Reversible Gene Expression in Chlamydomonas reinhardtii
- Dissection of the Blue-Light-Dependent Signal-Transduction Pathway Involved in Gametic Differentiation of Chlamydomonas reinhardtii.
- The ARG1-LIKE2 Gene of Arabidopsis Functions in a Gravity Signal Transduction Pathway That Is Genetically Distinct from the PGM Pathway1
- Enhanced Low Oxygen Survival in Arabidopsis through Increased Metabolic Flux in the Fermentative Pathway1
- Copper-Dependent Iron Assimilation Pathway in the Model Photosynthetic Eukaryote Chlamydomonas reinhardtii