Specificity landscapes of 40 R2R3‐MYBs reveal how paralogs target different cis ‐elements by homodimeric binding

作者：Tian Li, Hao Chen, Nana Ma, Dingkun Jiang, Jiacheng Wu, Xinfeng Zhang, Hao Li, Jiaqing Su, Piaojuan Chen, Qing Liu, Yuefeng Guan, Xiaoyue Zhu, Juncheng Lin, Jilin Zhang, Qing K. Wang, Honghong Guo, Fangjie Zhu · 发表于：iMeta · 年份：2025 · DOI：10.1002/imt2.70009 · 被引用次数：13 · 研究领域：CRISPR and Genetic Engineering、Genomics and Chromatin Dynamics、Protein Degradation and Inhibitors

Abstract Paralogous transcription factors (TFs) frequently recognize highly similar DNA motifs. Homodimerization can help distinguish them according to their different dimeric configurations. Here, by studying R2R3‐MYB TFs, we show that homodimerization can also directly change the recognized DNA motifs to distinguish between similar TFs. By high‐throughput SELEX, we profiled the specificity landscape for 40 R2R3‐MYBs of subfamily VIII and curated 833 motif models. The dimeric models show that homodimeric binding has evoked specificity changes for AtMYBs. Focusing on AtMYB2 as an example, we show that homodimerization has modified its specificity and allowed it to recognize additional cis‐ regulatory sequences that are different from the closely related CCWAA‐box AtMYBs and are unique among all AtMYBs. Genomic sites described by the modified dimeric specificities of AtMYB2 are conserved in evolution and involved in AtMYB2‐specific transcriptional activation. Collectively, this study provides rich data on sequence preferences of VIII R2R3‐MYBs and suggests an alternative mechanism that guides closely related TFs to respective cis‐ regulatory sites.