Overexpression of the gene encoding GTP: mannose-1-phosphate guanyltransferase, mpg1, increases cellular GDP-mannose levels and protein mannosylation in Trichoderma reesei

Anna Zakrzewska, Grazyna Palamarczyk, Hubert Krotkiewski, Ewa Zdebska, Markku Saloheimo, Merja Penttilä, Joanna S. Kruszewska

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20 Citations (Scopus)


To elucidate the regulation and limiting factors in the glycosylation of secreted proteins, the mpg1 and dpm1 genes from Trichoderma reesei (Hypocrea jecorina) encoding GTP:α-D-mannose-1-phosphate guanyltransferase and dolichyl phosphate mannose synthase (DPMS), respectively, were overexpressed in T. reesei. No significant increases were observed in DPMS activity or protein secretion in dpm1-overexpressing transformants, whereas overexpression of mpg1 led to a twofold increase in GDP-mannose (GDPMan) levels. GDPMan was effectively utilized by mannnosyltransferases and resulted in hypermannosylation of secreted proteins in both N and O glycosylation. Overexpression of the mpg1 gene also increased the transcription of the dpm1 gene and DPMS activity. Our data indicate that the level of cellular GDPMan can play a major regulatory role in protein glycosylation in T. reesei.

Original languageEnglish
Pages (from-to)4383-4389
Number of pages7
JournalApplied and Environmental Microbiology
Issue number8
Publication statusPublished - 1 Aug 2003
MoE publication typeA1 Journal article-refereed


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