The rice OsHsfC1b gene is well known as the "heat shock transcription factor gene" and regulates salt tolerance and development in Oryza sativa ssp. japonica.
OsHsfC1b plays a role in ABA-mediated salt stress tolerance in rice.The role of class C HSFs in stress response is currently unknown;however, expression patterns of class C HSF genes from rice suggest, in addition to a role in the heat shock response, a participation in non-thermal stress responses such as salt,drought and oxidative stress.In particular, OsHsfC1b and OsHsf2b are highly responsive to salt and drought stress.
Furthermore, OsHsfC1b is involved in the response to osmotic stress and is required for plant growth under non-stress conditions.In contrast to class A HSFs, OsHsfC1b acts as a positive regulator of growth under standard growth conditions. We therefore propose that class C HSFs play an opposite role to class A members in plant growth control.
Expression of OsHsfC1b was induced by salt, mannitol and ABA, but not by H2O2.OsHsfC1b was significantly induced in roots after 30 min treatment with salt, mannitol and ABA. In addition, OsHsfC1b was also significantly upregulated in leaves after 30 min of salt treatment. After 3 h,the expression level of OsHsfC1b in roots was significantly increased by salt and ABA, but not by mannitol. Again,salt stress resulted in an upregulation of expression in leaves. H2O2 had no effect on OsHsfC1b transcript level.
OsHsfC1b is localized in the nucleus in the absence of stress,which indicates that a stress-dependent modification is not required for nuclear accumulation.
To determine the phylogenetic relationship among the OsHsfs, neighbor-joining phylogenetic trees were constructed using the amino acid sequences of DBD, the HR-A/B region, and the linker between them . As expected, the classes A, B and C Hsfs formed three individual clusters. Furthermore, the class A Hsfs were divided into two sub-clusters. In a previous study, the N-terminal part and C-terminal part of DBD and HR-A/B regions were used separately to draw phylogenetic trees. Although most proteins fixed their positions in the different phylogenetic trees, a few Hsfs changed theirpositions (Nover et al., 2001). Similar phenomenon was also observed on the OsHsfs (data not shown). A more convinced relationship of the Hsfs was revealed by combining the DBD, HR-A/B, and the flexible linker between DBD and HR-A/B.
A typical Hsf protein contains a modular structure with an N-terminal DNA-binding domain (DBD), an adjacent bipartite oligomerization domain composed of heptads repeat of hydrophobic amino acid residues (HR-A/B), a nuclear localization signal (NLS) essential for nuclear uptake of the protein, a nuclear export signal (NES),and in many cases a less conserved C-terminal activation domain (CTAD) rich in aromatic, hydrophobic and acidic amino acids (AHA) that have been reported to be crucial for activation function.Based on the conservative DBD and the HR-A/B regions, 21 putative Hsfs from the Arabidopsis,23 from rice, and 18 from tomato have been identified through the genome-wide analysis. Plant Hsf gene family is divided into three classes, HsfA, HsfB, and HsfC, according to their protein structures.HsfA and HsfC have insertions of 21 and 7 amino acids, between the hydrophobic regions HR-A and HR-B,respectively. HsfB and HsfC are also characterized bylack of AHA motifs in their C-terminal regions(CTRs).
Labs working on this gene
Institute of Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Str. 24–25, 14476 Potsdam, Germany
Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476 Potsdam, Germany
CIRAD, UMR AGAP, Avenue Agropolis, 34398 Montpellier, Cedex 5, France
State Key Laboratory of Plant Physiology and Biochemistry, College of Life Science, Zhejiang University, Hangzhou 310058, China
National Center for Gene Research and Shanghai Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 500 Caobao Road, Shanghai 200233, China
State Key Lab of Rice Biology, China National Rice Research Institute, 359 Tiyuchang Road, Hangzhou 30016, China
Graduate School of the Chinese Academy of Sciences, Beijing 100039, China
Biocenter of the Goethe University, Frankfurt/Main, Germany
- Romy Schmidt, Jos H.M. Schippers, Annelie Welker, Delphine Mieulet, Emmanuel Guiderdoni and Bernd Mueller-Roeber,et al.（2009）Transcription factor OsHsfC1b regulates salt tolerance and development in Oryza sativa ssp. japonica.AoB PLANTS 011:1-17.
- Wenhuo Hua, Guocheng Hua, Bin Han et al.(2009)Genome-wide survey and expression profiling of heat shock proteins and heat shock factors revealed overlapped and stress specific response under abiotic stresses in rice.Journal of Zhejiang University SCIENCE B 10:291-300.
- Chuang WANG, Qian ZHANG, Hui-xia SHOU et al.(2009)Identification and expression analysis of OsHsfs in rice.Plant Science 176:583–590.
- Nover, L., Bharti, K., Doring, P., Mishra, S.K., Ganguli, A.,Scharf, K.D. et al.(2001)Arabidopsis and the heat stress transcription factor world: how many heat stress transcription factors do we need?Cell Stress Chaperones 6:177-89.