Characterization of secretory genes ypt1/yptA and nsf1/nsfA from two filamentous fungi: induction of secretory pathway genes of Trichoderma reesei under secretion stress conditions.
Two genes involved in protein secretion, encoding the Rab protein YPT1/YPTA and the general fusion factor NSFI/NSFA, were characterized from two filamentous fungi, Trichoderma reesei and Aspergillus niger var. awamori. The isolated genes showed a high level of conservation with their Saccharomyces cerevisiae and mammalian counterparts, and T. reesei ypt1 was shown to complement yeast Ypt1p depletion. The transcriptional regulation of the T. reesei ypt1, nsf1, and sar1 genes, involved in protein trafficking, was studied with mycelia treated with the folding inhibitor dithiothreitol (DTT) and with brefeldin A, which inhibits membrane traffic between the endoplasmic reticulum and Golgi complex. The well-known inducer of the yeast and T. reesei unfolded protein response (UPR), DTT, induced the nsf1 gene and the protein disulfide isomerase gene, pdi1, in both of the experiments, and sar1 mRNA increased in only one experiment under strong UPR induction. The ypt1 mRNA did not show a clear increase during DTT treatment. Brefeldin A strongly induced pdi1 and all of the intracellular trafficking genes studied. These results suggest the possibility that the whole secretory pathway of T. reesei could be induced at the transcriptional level by stress responses caused by protein accumulation in the secretory pathway.
Saloheimo
Markku
M
VTT Biotechnology, Espoo, Finland. Genencor International, Inc., Palo Alto, California, USA. Markku.Saloheimo@vtt.fi
Wang
Huaming
H
Valkonen
Mari
M
Vasara
Tuija
T
Huuskonen
Anne
A
Riikonen
Marjukka
M
Pakula
Tiina
T
Ward
Michael
M
Penttilä
Merja
M
D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D001234:Aspergillus niger / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D003470:Culture Media; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D018869:Heat-Shock Response; D008969:Molecular Sequence Data; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic; D014242:Trichoderma / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D033921:Vesicular Transport Proteins / Q000235:genetics / Q000378:metabolism; D020691:rab GTP-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D003470:Culture Media; D005656:Fungal Proteins; D029701:Saccharomyces cerevisiae Proteins; D033921:Vesicular Transport Proteins; D000251:Adenosine Triphosphatases; C064404:SEC18 protein, S cerevisiae; C060755:YPT1 protein, S cerevisiae; D020691:rab GTP-Binding Proteins