TY - JOUR
T1 - Unfolded protein response is required for Aspergillus oryzae growth under conditions inducing secretory hydrolytic enzyme production
AU - Tanaka, Mizuki
AU - Shintani, Takahiro
AU - Gomi, Katsuya
N1 - Funding Information:
We thank Osamu Mizutani for kindly providing the Δ ligD :: loxP pyrG − mutant strain and Tomoko Shintani for technical assistance. This work was supported in part by JSPS KAKENHI (Grant no. 17019001 ), Program for Promotion of Basic and Applied Researches for Innovations in Bio-oriented Industry , and Science and Technology Research Promotion Program for Agriculture, Forestry, Fisheries, and Food Industry .
PY - 2015/12/1
Y1 - 2015/12/1
N2 - Unfolded protein response (UPR) is an intracellular signaling pathway for adaptation to endoplasmic reticulum (ER) stress. In yeast UPR, Ire1 cleaves the unconventional intron of HAC1 mRNA, and the functional Hac1 protein translated from the spliced HAC1 mRNA induces the expression of ER chaperone genes and ER-associated degradation genes for the refolding or degradation of unfolded proteins. In this study, we constructed an ireA (IRE1 ortholog) conditionally expressing strain of Aspergillus oryzae, a filamentous fungus producing a large amount of amylolytic enzymes, and examined the contribution of UPR to ER stress adaptation under physiological conditions. Repression of ireA completely blocked A. oryzae growth under conditions inducing the production of hydrolytic enzymes, such as amylases and proteases. This growth defect was restored by the introduction of unconventional intronless hacA (hacA-i). Furthermore, UPR was observed to be induced by amylolytic gene expression, and the disruption of the transcriptional activator for amylolytic genes resulted in partial growth restoration of the ireA-repressing strain. In addition, a homokaryotic ireA disruption mutant was successfully generated using the strain harboring hacA-i as a parental host. These results indicated that UPR is required for A. oryzae growth to alleviate ER stress induced by excessive production of hydrolytic enzymes.
AB - Unfolded protein response (UPR) is an intracellular signaling pathway for adaptation to endoplasmic reticulum (ER) stress. In yeast UPR, Ire1 cleaves the unconventional intron of HAC1 mRNA, and the functional Hac1 protein translated from the spliced HAC1 mRNA induces the expression of ER chaperone genes and ER-associated degradation genes for the refolding or degradation of unfolded proteins. In this study, we constructed an ireA (IRE1 ortholog) conditionally expressing strain of Aspergillus oryzae, a filamentous fungus producing a large amount of amylolytic enzymes, and examined the contribution of UPR to ER stress adaptation under physiological conditions. Repression of ireA completely blocked A. oryzae growth under conditions inducing the production of hydrolytic enzymes, such as amylases and proteases. This growth defect was restored by the introduction of unconventional intronless hacA (hacA-i). Furthermore, UPR was observed to be induced by amylolytic gene expression, and the disruption of the transcriptional activator for amylolytic genes resulted in partial growth restoration of the ireA-repressing strain. In addition, a homokaryotic ireA disruption mutant was successfully generated using the strain harboring hacA-i as a parental host. These results indicated that UPR is required for A. oryzae growth to alleviate ER stress induced by excessive production of hydrolytic enzymes.
KW - Aspergillus oryzae
KW - Endoplasmic reticulum stress
KW - HacA
KW - Hydrolytic enzyme production
KW - IreA
KW - Unfolded protein response
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U2 - 10.1016/j.fgb.2015.10.003
DO - 10.1016/j.fgb.2015.10.003
M3 - Article
C2 - 26496881
AN - SCOPUS:84946209566
VL - 85
SP - 1
EP - 6
JO - Fungal Genetics and Biology
JF - Fungal Genetics and Biology
SN - 1087-1845
ER -