6kks
Structural insights into target DNA recognition by R2R3-type MYB transcription factor
Structural highlights
FunctionWER_ARATH Transcription activator, when associated with BHLH2/EGL3/MYC146 or BHLH12/MYC1. Involved in epidermal cell fate specification in roots and hypocotyl. Together with GL3 or BHLH2, promotes the formation of non-hair developing cells (atrichoblasts) et the N position in root epidermis. Regulates stomata spatial distribution in hypocotyls. Binds to the WER-binding sites (WBS) promoter regions and activates the transcription of target genes such as GL2 and of CPC.[1] [2] [3] [4] [5] [6] Publication Abstract from PubMedAs the largest group of MYB family transcription factors, R2R3-MYB proteins play essential roles during plant growth and development. However, the structural basis underlying how R2R3-MYBs recognize the target DNA remains elusive. Here, we report the crystal structure of Arabidopsis WEREWOLF (WER), an R2R3-MYB protein, in complex with its target DNA. Structural analysis showed that the third alpha-helices in both the R2 and R3 repeats of WER fit in the major groove of the DNA, specifically recognizing the DNA motif 5'-AACNGC-3'. In combination with mutagenesis, in vitro binding and in vivo luciferase assays, we showed that K55, N106, K109 and N110 are critical for the function of WER. Although L59 of WER is not involved in DNA binding in the structure, ITC analysis suggested that L59 plays an important role in sensing DNA methylation at the fifth position of cytosine (5mC). Like 5mC, methylation at the sixth position of adenine (6mA) in the AAC element also inhibits the interaction between WER and its target DNA. Our study not only unravels the molecular basis of how WER recognizes its target DNA, but also suggests that 5mC and 6mA modifications may block the interaction between R2R3-MYB transcription factors and their target genes. Structural insights into target DNA recognition by R2R3-MYB transcription factors.,Wang B, Luo Q, Li Y, Yin L, Zhou N, Li X, Gan J, Dong A Nucleic Acids Res. 2019 Nov 16. pii: 5626523. doi: 10.1093/nar/gkz1081. PMID:31733060[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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