Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành y học dành cho các bạn tham khảo đề tài: A single amino acid change within the R2 domain of the VvMYB5b transcription factor modulates affinity for protein partners and target promoters selectivity | Hichri et al. BMC Plant Biology 2011 11 117 http 1471 -2229 11 117 BMC Plant Biology RESEARCH ARTICLE Open Access A single amino acid change within the R2 domain of the VvMYB5b transcription factor modulates affinity for protein partners and target promoters selectivity Imène Hichri1 2 3 Laurent Deluc4 Franpois Barrieu1 2 3 Jochen Bogs5 6 Ali Mahjoub1 2 3 Farid Regad7 8 -1-1 z 8 I- z Bernard Gallois Thierry Granier Claudine Trossat-Magnin Eric Gomès and Virginie Lauvergeat Abstract Background Flavonoid pathway is spatially and temporally controlled during plant development and the transcriptional regulation of the structural genes is mostly orchestrated by a ternary protein complex that involves three classes of transcription factors R2-R3-MYB bHLH and WDR . In grapevine Vitis vinifera L. several MYB transcription factors have been identified but the interactions with their putative bHLH partners to regulate specific branches of the flavonoid pathway are still poorly understood. Results In this work we describe the effects of a single amino acid substitution R69L located in the R2 domain of VvMYB5b and predicted to affect the formation of a salt bridge within the protein. The activity of the mutated protein name VvMYB5bL the native protein being referred as VvMYB5bR was assessed in different in vivo systems yeast grape cell suspensions and tobacco. In the first two systems VvMYB5bL exhibited a modified trans-activation capability. Moreover using yeast two-hybrid assay we demonstrated that modification of VvMYB5b transcriptional properties impaired its ability to correctly interact with VvMYC1 a grape bHLH protein. These results were further substantiated by overexpression of VvMYB5bR and VvMYB5bL genes in tobacco. Flowers from 35S VvMYB5bL transgenic plants showed a distinct phenotype in comparison with 35S VvMYB5bR and the control plants. Finally significant differences in transcript abundance of flavonoid metabolism genes .
