Traynor, Aimee M. and Sarikaya-Bayram, Özlem and Bayram, Ozgur and Antonio Calera, José and Doyle, Sean
(2023)
Proteomic dissection of the role of GliZ in gliotoxin biosynthesis in Aspergillus fumigatus.
Fungal Genetics and Biology, 166.
p. 103795.
ISSN 1087-1845
Abstract
Gliotoxin (GT) biosynthesis in fungi is encoded by the gli biosynthetic gene cluster. While GT addition autoinduces
biosynthesis, Zn2+ has been shown to attenuate cluster activity, and it was speculated that identification
of Zn2Cys6 binuclear transcription factor GliZ binding partners might provide insight into this observation. Using
the Tet-ON induction system, doxycycline (DOX) presence induced GliZ fusion protein expression in, and recovery
of GT biosynthesis by, A. fumigatus ΔgliZ::HA-gliZ and ΔgliZ::TAP-gliZ strains, respectively. Quantitative
RT-PCR confirmed that DOX induces gli cluster gene expression (n = 5) in both A. fumigatus HA-GliZ and TAPGliZ
strains. GT biosynthesis was evident in Czapek-Dox and in Sabouraud media, however tagged GliZ protein
expression was more readily detected in Sabouraud media. Unexpectedly, Zn2+ was essential for GliZ fusion
protein expression in vivo, following 3 h DOX induction. Moreover, HA-GliZ abundance was significantly higher
in either DOX/GT or DOX/Zn2+, compared to DOX-only. This suggests that while GT induction is still intact, Zn2+
inhibition of HA-GliZ production in vivo is lost. Co-immunoprecipitation revealed that GT oxidoreductase GliT
associates with GliZ in the presence of GT, suggesting a potential protective role. Additional putative HA-GliZ
interacting proteins included cystathionine gamma lyase, ribosomal protein L15 and serine hydroxymethyltransferase
(SHMT). Total mycelial quantitative proteomic data revealed that GliT and GtmA, as well as several
other gli cluster proteins, are increased in abundance or uniquely expressed with GT addition. Proteins involved
in sulphur metabolism are also differentially expressed with GT or Zn2+ presence. Overall, we disclose that under
DOX induction GliZ functionality is unexpectedly evident in zinc-replete media, subject to GT induction and that
GliT appears to associate with GliZ, potentially to prevent dithiol gliotoxin (DTG)-mediated GliZ inactivation by
zinc ejection.
| Item Type: |
Article
|
| Keywords: |
Quantitative proteomics;
Fungal pathogen;
Nutritional immunity;
Transcription factor;
Zinc;
LC-MS;
Mycotoxin; |
| Academic Unit: |
Faculty of Science and Engineering > Biology |
| Item ID: |
18452 |
| Identification Number: |
https://doi.org/10.1016/j.fgb.2023.103795 |
| Depositing User: |
Ozgur Bayram
|
| Date Deposited: |
30 Apr 2024 13:28 |
| Journal or Publication Title: |
Fungal Genetics and Biology |
| Publisher: |
Elsevier |
| Refereed: |
Yes |
| URI: |
|
| Use Licence: |
This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available
here |
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