TY - JOUR
T1 - Heat stress transcription factors from tomato can functionally replace HSF1 in the yeast Saccharomyces cerevisiae
AU - Boscheinen, O.
AU - Lyck, R.
AU - Queitsch, C.
AU - Treuter, E.
AU - Zimarino, V.
AU - Scharf, K. D.
PY - 1997
Y1 - 1997
N2 - The fact that yeast HSF1 is essential for survival under nonstress conditions can be used to test heterologous Hsfs for the ability to substitute for the endogenous protein. Our results demonstrate that like Hsf of Drosophila, tomato Hsfs A1 and A2 can functionally replace the corresponding yeast protein, but Hsf B1 cannot. In addition to survival at 28°C, we checked the transformed yeast strains for temperature sensitivity of growth, induced thermotolerance and activator function using two different lacZ reporter constructs. Tests with full-length Hsfs were supplemented by assays using mutant Hsfs lacking parts of their C-terminal activator region or oligomerization domain, or containing amino acid substitutions in the DNA-binding domain. Remarkably, results with the yeast system are basically similar to those obtained by the analysis of the same Hsfs as transcriptional activators in a tobacco protoplast assay. Most surprising is the failure of HstB1 to substitute for the yeast Hsf. The defect can be overcome by addition to HsfB1 of a short C-terminal peptide motif from HsfA2 (34 amino acid residues), which represents a type of minimal activator necessary for interaction with the yeast transcription apparatus. Deletion of the oligomerization domain (HR-A/B) does not interfere with Hsf function for survival or growth at higher temperatures. But monomeric Hsf has a markedly reduced affinity for DNA as shown by lacZ reporter and band-shift assays.
AB - The fact that yeast HSF1 is essential for survival under nonstress conditions can be used to test heterologous Hsfs for the ability to substitute for the endogenous protein. Our results demonstrate that like Hsf of Drosophila, tomato Hsfs A1 and A2 can functionally replace the corresponding yeast protein, but Hsf B1 cannot. In addition to survival at 28°C, we checked the transformed yeast strains for temperature sensitivity of growth, induced thermotolerance and activator function using two different lacZ reporter constructs. Tests with full-length Hsfs were supplemented by assays using mutant Hsfs lacking parts of their C-terminal activator region or oligomerization domain, or containing amino acid substitutions in the DNA-binding domain. Remarkably, results with the yeast system are basically similar to those obtained by the analysis of the same Hsfs as transcriptional activators in a tobacco protoplast assay. Most surprising is the failure of HstB1 to substitute for the yeast Hsf. The defect can be overcome by addition to HsfB1 of a short C-terminal peptide motif from HsfA2 (34 amino acid residues), which represents a type of minimal activator necessary for interaction with the yeast transcription apparatus. Deletion of the oligomerization domain (HR-A/B) does not interfere with Hsf function for survival or growth at higher temperatures. But monomeric Hsf has a markedly reduced affinity for DNA as shown by lacZ reporter and band-shift assays.
KW - Heat stress
KW - Thermotolerance
KW - Tomato
KW - Transcription factor
KW - Yeast
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U2 - 10.1007/s004380050503
DO - 10.1007/s004380050503
M3 - Article
C2 - 9268023
AN - SCOPUS:0030877053
VL - 255
SP - 322
EP - 331
JO - Molecular Genetics and Genomics
JF - Molecular Genetics and Genomics
SN - 1617-4615
IS - 3
ER -