title: Binding affinities and interactions among different heat shock element types and heat shock factors in rice (Oryza sativa L.).
abstract: Binding of heat shock factors (Hsfs) to heat shock elements (HSEs) leads to transcriptional regulation of heat shock genes. Genome-wide, 953 rice genes contain perfect-type, 695 genes gap-type and 1584 genes step-type HSE sequences in their 1-kb promoter region. The rice genome contains 13 class A, eight class B and four class C Hsfs (OsHsfs) and has OsHsf26 (which is of variant type) genes. Chemical cross-linking analysis of in vitro synthesized OsHsf polypeptides showed formation of homotrimers of OsHsfA2c, OsHsfA9 and OsHsfB4b proteins. Binding analysis of polypeptides with oligonucleotide probes containing perfect-, gap-, and step-type HSE sequences showed that OsHsfA2c, OsHsfA9 and OsHsfB4b differentially recognize various model HSEs as a function of varying reaction temperatures. The homomeric form of OsHsfA2c and OsHsfB4b proteins was further noted by the bimolecular fluorescence complementation approach in onion epidermal cells. In yeast two-hybrid assays, OsHsfB4b showed homomeric interaction as well as distinct heteromeric interactions with OsHsfA2a, OsHsfA7, OsHsfB4c and OsHsf26. Transactivation activity was noted in OsHsfA2c, OsHsfA2d, OsHsfA9, OsHsfC1a and OsHsfC1b in yeast cells. These differential patterns pertaining to binding with HSEs and protein-protein interactions may have a bearing on the cellular functioning of OsHsfs under a range of different physiological and environmental conditions.
authors: Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, India.
authors: Dheeraj
authors: D
authors: Mittal
authors: Yasuaki
authors: Y
authors: Enoki
authors: Dhruv
authors: D
authors: Lavania
authors: Amanjot
authors: A
authors: Singh
authors: Hiroshi
authors: H
authors: Sakurai
authors: Anil
authors: A
authors: Grover
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D003432:Cross-Linking Reagents / Q000737:chemistry; D018744:DNA, Plant / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D024202:Electrophoretic Mobility Shift Assay; D017343:Genes, Plant; D000076249:Heat Shock Transcription Factors; D006360:Heat-Shock Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018869:Heat-Shock Response; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D019697:Onions / Q000166:cytology / Q000378:metabolism; D012275:Oryza / Q000378:metabolism*; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D019441:Plant Epidermis / Q000166:cytology / Q000378:metabolism; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D020218:Response Elements; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation; D020798:Two-Hybrid System Techniques
chemical_list: D001426:Bacterial Proteins; D003432:Cross-Linking Reagents; D018744:DNA, Plant; D004268:DNA-Binding Proteins; D000076249:Heat Shock Transcription Factors; D006360:Heat-Shock Proteins; D008164:Luminescent Proteins; D010446:Peptide Fragments; D010940:Plant Proteins; D011994:Recombinant Proteins; D014157:Transcription Factors; C054562:yellow fluorescent protein, Bacteria