Abstract
Trichoderma reesei is an industrial protein production host known for
its exceptional protein secretion capability. This study aims at uncovering
the transcriptional responses occurring in T. reesei cells exposed to
secretion stress and comparing these responses to similar experiments carried
out in S. cerevisiae. Secretion stress is caused by compromised protein
folding or transport in the secretory pathway. It induces a number of genes
involved in different aspects of secretion through the unfolded protein
response (UPR) pathway. In T. reesei it has also been shown that secretion
stress down-regulates genes encoding secreted proteins.
We constructed cDNA subtraction libraries and made cDNA-AFLP (amplified
fragment length polymorphism) experiments from cells under secretion stress. A
transformant expressing human tissue plasminogen activator (tPA), treatment
with the chemical DTT (dithiothreitol) that prevents correct protein folding
and a transformant over-expressing IREI protein (sensor protein of the
UPR_pathway) were analysed. Around two hundred unique ESTs were retrieved by
these methods and the expression pattern of about 50 was confirmed by Northern
experiments. A rank sum test for the Northern data was used to define those
genes that show upregulation in all the three conditions. Data from DTT and
tunicamycin treatment, foreign protein production and IRE1 and HAC1 (UPR
transcription factor) deletion experiments in S. cerevisiae were combined from
litterature.
The transcriptional responses of T. reesei and S. cerevisiae show clear
overlap, especially with respect to genes involved in protein translocation,
folding and glycosylation in the ER. However, there seems to be major
differences in regulation of amino acid biosynthesis and nucleosome genes. The
GCN4/CPC1 transcription factor and a limited set of its putative target genes
are induced only in T. reesei. This response points to the upregulation of
glutathione synthesis to relieve oxidative stress caused by compromised
protein folding. Interestingly also a set of nucleosome genes is upregulated
in T. reesei without a clear connection to cell cycle.
Original language | English |
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Pages | 190 |
Publication status | Published - 2004 |
MoE publication type | Not Eligible |
Event | 7th European Conference on Fungal Genetics - Copenhagen, Denmark Duration: 17 Apr 2004 → 20 Apr 2004 |
Conference
Conference | 7th European Conference on Fungal Genetics |
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Country/Territory | Denmark |
City | Copenhagen |
Period | 17/04/04 → 20/04/04 |