tailieunhanh - Báo cáo khoa học: Binding affinities and interactions among different heat shock element types and heat shock factors in rice (Oryza sativa L.)

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. | IFEBS Journal Binding affinities and interactions among different heat shock element types and heat shock factors in rice Oryza sativa L. Dheeraj Mittal1 Yasuaki Enoki2 Dhruv Lavania1 Amanjot Singh1 Hiroshi Sakurai2 and Anil Grover1 1 Department of Plant Molecular Biology University of Delhi South Campus New Delhi India 2 Division of Health Sciences Graduate Schoolof MedicalScience Kanazawa University Japan Keywords heat shock heat shock element heat shock protein heat shock transcription factor rice Oryza sativa Correspondence A. Grover Department of Plant Molecular Biology University of Delhi South Campus New Delhi 110021 India Fax 91-11-24115270 Tel 91-11-24117693 24115097 E-mail Received 9 May 2011 revised 27 June 2011 accepted 29 June 2011 doi 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 OsH-sfB4c and OsHsf26. Transactivation activity was noted in OsHsfA2c OsH-sfA2d OsHsfA9 OsHsfC1a and OsHsfC1b in