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Post‐transcriptional control of a glucoamylase gene from Trichoderma harzianum under stress conditions
Author(s) -
Dana María de las Mercedes,
PintorToro José A.
Publication year - 2005
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2005.04682.x
Subject(s) - biology , open reading frame , gene , trichoderma harzianum , transcription (linguistics) , untranslated region , heterologous , signal peptide , messenger rna , genetics , microbiology and biotechnology , peptide sequence , botany , linguistics , philosophy , biological pest control
Summary We have examined the regulation of Trichoderma harzianum glucoamylase gene ( Gla66 ) in response to different growth conditions. Transcription of the Gla66 gene is initiated from two different sites, yielding two transcripts of 2.1 kb and 2.6 kb respectively. The 2.1 kb mRNA ( ST ) encodes for an extracellular glucoamylase of 66 kDa. This protein shows the domains conserved in other fungal glucoamylases: a signal peptide responsible for protein secretion and a catalytic domain, both joined by a linker region. The longest transcript ( LT ) is untranslated, it contains an unusually extended 5′‐untranslated region and is transcribed under stress and growth limiting conditions. The translational control of LT could be defined by the presence of four upstream open reading frames (uORFs) in its 5′‐leader sequence. The analysis of these uORFs in a yeast heterologous system shows that two of these uORFs prevent the Gla66 translation under unfavourable growth conditions, when the LT transcript is accumulated.