Please use this identifier to cite or link to this item: https://hdl.handle.net/1959.11/18000
Title: Distinct roles for the p53-like transcription factor XprG and autophagy genes in the response to starvation
Contributor(s): Katz, Margaret E  (author); Buckland, Rebecca (author); Hunter, Cameron C (author); Todd, Richard B (author)
Publication Date: 2015
DOI: 10.1016/j.fgb.2015.08.006
Handle Link: https://hdl.handle.net/1959.11/18000
Abstract: Autophagy and autolysis are two cannibalistic pathways which allow filamentous fungi to obtain nutrients once environmental nutrient sources are exhausted. In Aspergillus nidulans, the effects of mutations in two key autophagy genes, atgA, the ATG1 ortholog, and atgH, the ATG8 ortholog, were compared with mutations in xprG, which encodes a transcriptional activator that plays a key role in autolysis. The antifungal drug rapamycin induces autophagy in a range of organisms. Mutations in atgA and atgH did not alter sensitivity to rapamycin, which inhibits growth and asexual spore production (conidiation), indicating that autophagy is not required for rapamycin sensitivity in A. nidulans. In contrast, inhibition of conidiation by rapamcyin was partially suppressed by the xprG1 gain-of-function mutation, indicating that XprG acts in the pathway(s) affected by rapamycin. It was anticipated that the absence of an intact autophagy pathway would accelerate the response to starvation. However, extracellular and intracellular protease production in response to carbon or nitrogen starvation was not increased in the atgAD and atgHD mutants, and the onset of autolysis was not accelerated. Compared to wild-type strains and the xprGD and xprG1 mutants, conidiation of the autophagy mutants was reduced in carbon- or nitrogen-limiting conditions but not during growth on nutrient-sufficient medium. Nuclear localization of the global nitrogen regulator AreA in response to nitrogen starvation was blocked in the xprG2 loss-of-function mutant, but not in the atgHD mutant. Conversely, the atgAD mutation but not the xprGD mutation prevented vacuolar accumulation of GFP-AtgH, a hallmark of autophagy. These results indicate that in A. nidulans there is little interaction between autophagy and autolysis and the two pathways are activated in parallel during starvation.
Publication Type: Journal Article
Source of Publication: Fungal Genetics and Biology, v.83, p. 10-18
Publisher: Academic Press
Place of Publication: United States of America
ISSN: 1096-0937
1087-1845
Fields of Research (FoR) 2008: 060405 Gene Expression (incl Microarray and other genome-wide approaches)
060503 Microbial Genetics
060505 Mycology
Fields of Research (FoR) 2020: 310505 Gene expression (incl. microarray and other genome-wide approaches)
310704 Microbial genetics
310705 Mycology
Socio-Economic Objective (SEO) 2008: 970106 Expanding Knowledge in the Biological Sciences
Socio-Economic Objective (SEO) 2020: 280102 Expanding knowledge in the biological sciences
Peer Reviewed: Yes
HERDC Category Description: C1 Refereed Article in a Scholarly Journal
Appears in Collections:Journal Article

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