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Title: Genomic responses to arsenic in Synechocystis      
dateReleased:
05-13-2014
description:
Arsenic is an ubiquitous contaminant and a toxic metalloid which presents two main redox states in nature: arsenite [AsIII] and arsenate [AsV]. Arsenic resistance in Synechocystis sp. strain PCC 6803 is mediated by the arsBHC operon and two additional arsenate reductases encoded by the arsI1 and arsI2 genes. Here we describe the genome-wide responses in response to the presence of arsenate and arsenite in wild type and in mutants in the arsenic resistance system. Both forms of arsenic produced similar responses in the wild type strain including induction of several stress related genes and repression of energy generation processes. The responses observed in the arsB mutant strain were similar to the wild type in short term but were maintained in time while they were only transient in the wild type strain. In contrast, the responses observed in a strain lacking all arsenate reductases (the SARS12 strain) were somewhat different and included lower induction of genes involved in metal homeostasis and Fe-S cluster biogenesis. These results suggest that these two processes are targeted by arsenite in the wild type strain. Finally, analysis of the arsR mutant strain revealed that ArsR seems to only control 5 genes in the genome. Furthermore, over-expression of ArsB conferred hypersentivity to nickel, copper and cadmium in an arsR mutant strain. Analysis of genome-wide gene expression patterns in response to arsenic in WT and mutants involved in arsenic detoxification in the cyanobacterium Synechocystis sp PCC 6803. Cells treated with arsenate or arsenite for 1h. Details: WT cells were treated with 1 mM arsenite for 1 h and its expression profile compared to untreated cells (grown in BG11C media). The effects of arsenate were analyzed in the same way but using a modified BG11C media that constains 15% of the normal phosphate concentration (BG11C low phosphate). A reduction in the phosphate concentration in the media is essential to detect grow inhibition after arsenate addition. In the same way that for arsenite cells were treated with 50 mM arsenate for 1 h and their expression profile was compared to untreated cells. Expression profiles of mutant strains lacking arsB gene (SARSB strain; this strain is hypersensitive to arsenite because it lacks the arsenite exporter) or arsR gene (SARSR strain; this strain expresses the arsBHC constitutively) in control conditions and in response to arsenite addition were also analyzed. In addition the expression profiles of a mutant lacking arsenate reductases (SARS12 strain that has interrupted arsC, arsI1 and arsI2 genes; this strain is hypersensitive to arsenate) were analyzed in both control conditions and after addition of 50 mM arsenate.
privacy:
not applicable
aggregation:
instance of dataset
ID:
E-GEOD-51383
refinement:
raw
alternateIdentifiers:
51383
keywords:
functional genomics
dateModified:
06-03-2014
availability:
available
types:
gene expression
name:
Synechocystis sp. PCC 6803
ID:
A-GEOD-17790
name:
Agilent-019727 CBF Synechocystis OW_AT 15K Expression array (Probe name version)
accessURL: https://www.ebi.ac.uk/arrayexpress/files/E-GEOD-51383/E-GEOD-51383.raw.1.zip
storedIn:
ArrayExpress
qualifier:
gzip compressed
format:
TXT
accessType:
download
authentication:
none
authorization:
none
accessURL: https://www.ebi.ac.uk/arrayexpress/files/E-GEOD-51383/E-GEOD-51383.processed.1.zip
storedIn:
ArrayExpress
qualifier:
gzip compressed
format:
TXT
accessType:
download
authentication:
none
authorization:
none
accessURL: https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE51383
storedIn:
Gene Expression Omnibus
qualifier:
not compressed
format:
HTML
accessType:
landing page
primary:
true
authentication:
none
authorization:
none
abbreviation:
EBI
homePage: http://www.ebi.ac.uk/
ID:
SCR:004727
name:
European Bioinformatics Institute
homePage: https://www.ebi.ac.uk/arrayexpress/
ID:
SCR:002964
name:
ArrayExpress

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