The master regulator of the Unfolded Protein Response revisited

N.D.S.P. Carvalho, T.R. Jørgensen, M. Arentshorst, C.A.M.J.J van den Hondel, A.F.J. Ram

Author address: 

Institute of Biology Leiden


The Unfolded Protein Response (UPR) regulates gene expression in response to stress in the endoplasmic reticulum (ER). In Aspergillus niger the beta-zip transcription factor HacA plays a central role in the activation of genes involved in this pathway. Activation of HacA is mediated via an unconventional splicing event of 20 nucleotides in its mRNA. In the present study we engineered an A. niger strain that expresses only the activated form of HacA and we show that the removal of the 20 nucleotides results in a constitutive activation of the well established UPR target genes. The wild type strain (HacAWT) and the strain expressing the constitutive active form of HacA (HacACA) were cultured in glucose-limited batch cultures using bioreactors. Initially, HacA grew with the same specific growth rate (8776;0.22 h-1) as the wild type. However, halfway into the growth phase HacA shifted to linear growth. RNA from the batch cultures was isolated for transcriptomic analysis of the effect of expressing a constitutive activated HacA. Statistical analysis defined 1119 genes as differentially expressed (significance p

abstract No: 


Full conference title: 

    • ECFG 10th (2010)