AtfA bZIP-type transcription factor regulates oxidative and osmotic stress responses in Aspergillus nidulans.
The aim of the study was to demonstrate that the bZIP-type transcription factor AtfA regulates different types of stress responses in Aspergillus nidulans similarly to Atf1, the orthologous 'all-purpose' transcription factor of Schizosaccharomyces pombe. Heterologous expression of atfA in a S. pombe Deltaatf1 mutant restored the osmotic stress tolerance of fission yeast in surface cultures to the same level as recorded in complementation studies with the atf1 gene, and a partial complementation of the osmotic and oxidative-stress-sensitive phenotypes was also achieved in submerged cultures. AtfA is therefore a true functional ortholog of fission yeast's Atf1. As demonstrated by RT-PCR experiments, elements of both oxidative (e.g. catalase B) and osmotic (e.g. glycerol-3-phosphate dehydrogenase B) stress defense systems were transcriptionally regulated by AtfA in a stress-type-specific manner. Deletion of atfA resulted in oxidative-stress-sensitive phenotypes while the high-osmolarity stress sensitivity of the fungus was not affected significantly. In A. nidulans, the glutathione/glutathione disulfide redox status of the cells as well as apoptotic cell death and autolysis seemed to be controlled by regulatory elements other than AtfA. In conclusion, the orchestrations of stress responses in the aspergilli and in fission yeast share several common features, but further studies are needed to answer the important question of whether a fission yeast-like core environmental stress response also operates in the euascomycete genus Aspergillus.
Department of Microbial Biotechnology and Cell Biology, Faculty of Science and Technology, University of Debrecen, Debrecen, Hungary.
Anita
A
Balázs
Imre
I
Pócsi
Zsuzsanna
Z
Hamari
Eva
E
Leiter
Tamás
T
Emri
Márton
M
Miskei
Judit
J
Oláh
Viktória
V
Tóth
Nikoletta
N
Hegedus
Rolf A
RA
Prade
Mónika
M
Molnár
István
I
Pócsi
D051696:Activating Transcription Factors / Q000235:genetics / Q000378:metabolism*; D001233:Aspergillus nidulans / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism*; D001483:Base Sequence; D050976:Basic-Leucine Zipper Transcription Factors / Q000235:genetics* / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D005838:Genotype; D005978:Glutathione / Q000378:metabolism; D019803:Glutathione Disulfide / Q000378:metabolism; D007700:Kinetics; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000235:genetics; D010641:Phenotype; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D012331:RNA, Fungal / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D012194:RNA-Directed DNA Polymerase / Q000378:metabolism; D012568:Schizosaccharomyces / Q000235:genetics / Q000378:metabolism
D051696:Activating Transcription Factors; D050976:Basic-Leucine Zipper Transcription Factors; D005656:Fungal Proteins; D011506:Proteins; D012331:RNA, Fungal; D012333:RNA, Messenger; C079238:alcohol O-acetyltransferase; D012194:RNA-Directed DNA Polymerase; D005978:Glutathione; D019803:Glutathione Disulfide