NCBI Logo
GEO Logo
   NCBI > GEO > Accession DisplayHelp Not logged in | LoginHelp
GEO help: Mouse over screen elements for information.
          Go
Series GSE33792 Query DataSets for GSE33792
Status Public on Nov 22, 2011
Title SRE1 Regulates Iron-Dependent Gene Expression in the Fungal Pathogen Histoplasma capsulatum
Organism Histoplasma capsulatum
Experiment type Expression profiling by array
Summary Regulation of iron acquisition genes is critical for microbial survival under both iron-limiting conditions (to acquire essential iron) and iron-replete conditions (to limit iron toxicity). In fungi, iron acquisition genes are repressed under iron-replete conditions by a conserved GATA transcriptional regulator. Here we investigate the role of this transcription factor, Sre1, in the cellular responses of the fungal pathogen Histoplasma capsulatum to iron. We showed that cells in which SRE1 levels were diminished by RNA interference were unable to repress siderophore biosynthesis and utilization genes in the presence of abundant iron, and thus produced siderophores even under iron-replete conditions. Mutation of a GATA-containing consensus site found in the promoters of these genes also resulted in inappropriate gene expression under iron-replete conditions. Microarray analysis comparing control and SRE1-depleted strains under conditions of iron limitation or abundance revealed both iron-responsive genes and Sre1-dependent genes, which comprised distinct but overlapping sets. Iron-responsive genes included putative oxidoreductases, metabolic and mitochondrial enzymes, superoxide dismutase, and nitrosative-stress response genes; Sre1-dependent genes were of diverse function. Genes regulated by iron levels and Sre1 included all of the siderophore biosynthetic genes, a gene involved in reductive iron acquisition, an iron-responsive transcription factor, and two catalases. Based on transcriptional profiling and phenotypic analyses, we conclude that Sre1 plays a critical role in the regulation of both traditional iron-responsive genes and iron-independent pathways such as regulation of cell morphology. These data highlight the evolving realization that the effect of Sre1 orthologs on fungal biology extends beyond the iron regulon.
 
Overall design For microarray studies, initial cultures of HcLH120 (Control RNAi-1) or 123 (SRE1 RNAi-2) yeast cells were grown in 5 mL HMM, and then passaged 1:25 into 100 mL HMM. After 2 days of growth, the cultures were pelleted, washed in 100 mL of PBS, resuspended in 100 mL of mRPMI pH 6.5 and diluted to an OD600~2 in 1 L of mRPMI. After 24 hours of growth, 200 mL of culture was harvested for each of the three zero time points. Then the cultures were split into 2 X 400 mL, and 10 uM FeSO4 (final concentration) was added to one set of cultures. At each time point (.5, 1, 4, or 8 hours), 100 mL of culture was harvested for RNA extraction.
 
Contributor(s) Hwang LH, Seth E, Sil A
Citation(s) 22117028
Submission date Nov 17, 2011
Last update date Mar 23, 2012
Contact name Mark Voorhies
E-mail(s) mark.voorhies@ucsf.edu
Organization name University of California
Department Microbiology and Immunology
Lab Anita Sil
Street address 513 Parnassus, S472
City San Francisco
State/province CA
ZIP/Postal code 94143-0414
Country USA
 
Platforms (1)
GPL14901 UCSF/Sil lab-Histoplasma capsulatum-G217Borfs2
Samples (20)
GSM835834 wt_t=0_1
GSM835835 wt_t=0_2
GSM835836 wt_t=0_3
Relations
BioProject PRJNA148059

Download family Format
SOFT formatted family file(s) SOFTHelp
MINiML formatted family file(s) MINiMLHelp
Series Matrix File(s) TXTHelp

Supplementary file Size Download File type/resource
GSE33792_RAW.tar 29.1 Mb (http)(custom) TAR (of GPR)
Processed data included within Sample table

| NLM | NIH | GEO Help | Disclaimer | Accessibility |
NCBI Home NCBI Search NCBI SiteMap
External link. Please review our privacy policy.