Systems analysis of Chlamydomonas Cu nutrition reveals connections between Cu and multiple O2-dependent metabolic steps
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ABSTRACT: We used digital gene expression (NlaIII sequence tags) and RNA-Seq to compare the transcriptomes of Cu-replete vs. Cu–deficient Chlamydomonas wild-type cells to reveal dozens of mRNAs whose abundance is modified. Half of the corresponding genes are targets of CRR1, a master regulator of nutritional copper sensing, and are associated with candidate CRR1 binding sites. The targets include many plastid-localized proteins, like FDX5 encoding a ferredoxin isoform, and CGL78, encoding a protein conserved in the green lineage, indicative of modified plastid metabolism. Immunoblot analysis and proteome profiles recapitulate the transcriptome profiles. New evidence for Cu sparing is suggested by up-regulation of AOF1 encoding a copper-independent but flavin-dependent amine oxidase and down-regulation of two metal- binding proteins. Genes encoding redox proteins, many of which function in lipid metabolism, are over-represented, which is compatible with the role of Cu in biology. Lipid profiles indicate a CRR1-dependent increase in Cu-deficient cells in the proportion of unsaturated (16:2, 16:3, 16:4, 18:2) fatty acids at the expense of the more saturated (16:0, 16:1, 18:0) precursors, especially on plastid galactolipids, which validates the increased expression of acyl-ACP and plastid-localized w-6 desaturases. CRR1-independent changes in the transcriptome suggest a role for Cu in oxygen sensing in Chlamydomonas.
ORGANISM(S): Chlamydomonas reinhardtii
PROVIDER: GSE25124 | GEO | 2011/10/24
SECONDARY ACCESSION(S): PRJNA134525
REPOSITORIES: GEO
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