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Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành y học dành cho các bạn tham khảo đề tài: The Arabidopsis EAR-motif-containing protein RAP2.1 functions as an active transcriptional repressor to keep stress responses under tight control | Dong and Liu BMC Plant Biology 2010 10 47 http www.biomedcentral.com 1471-2229 10 47 BMC Plant Biology RESEARCH ARTICLE Open Access The Arabidopsis EAR-motif-containing protein RAP2.1 functions as an active transcriptional repressor to keep stress responses under tight control Chun-Juan Dong Jin-Yuan Liu Abstract Background Plants respond to abiotic stress through complex regulation of transcription including both transcriptional activation and repression. Dehydration-responsive-element binding protein DREB -type transcription factors are well known to play important roles in adaptation to abiotic stress. The mechanisms by which DREB-type transcription factors activate stress-induced gene expression have been relatively well studied. However little is known about how DREB-type transcriptional repressors modulate plant stress responses. In this study we report the functional analysis of RAP2.1 a DREB-type transcriptional repressor. Results RAP2.1 possesses an APETALA2 AP2 domain that binds to dehydration-responsive elements DREs and an ERF-associated amphiphilic repression EAR motif as the repression domain located at the C-terminus of the protein. Expression of RAP2.1 is strongly induced by drought and cold stress via an ABA-independent pathway. Arabidopsis plants overexpressing RAP2.1 show enhanced sensitivity to cold and drought stresses while rap2.1-1 and rap2.1-2 T-DNA insertion alleles result in reduced sensitivity to these stresses. The reduced stress sensitivity of the plant containing the rap2.1 allele can be genetically complemented by the expression of RAP2.1 but not by the expression of EAR-motif-mutated RAP2.1. Furthermore chromatin immunoprecipitation ChIP analysis has identified Responsive to desiccation Cold-regulated RD COR genes as downstream targets of RAP2.1 in vivo. Stress-induced expression of the RD COR genes is repressed by overexpression of RAP2.1 and is increased in plants expressing the rap2.1 allele. In addition RAP2.1 can negatively .
