• A group of MADS transcription factors (TFs) are believed to control temperature-mediated bud dormancy. These TFs, called DORMANCY-ASSOCIATED MADS-BOX (DAM), are encoded by genes similar to SHORT VEGETATIVE PHASE (SVP) from Arabidopsis. MADS proteins form transcriptional complexes whose combinatory composition defines their molecular function. However, how MADS multimeric complexes control the dormancy cycle in trees is unclear.
• Apple MdDAM and other dormancy-related MADS proteins form complexes with MdSVPa, which is essential for the ability of transcriptional complexes to bind to DNA. Sequential DNA-affinity purification sequencing (seq-DAP-seq) was performed to identify the genome-wide binding sites of apple MADS TF complexes. Target genes associated with the binding sites were identified by combining seq-DAP-seq data with transcriptomics datasets obtained using a glucocorticoid receptor fusion system, and RNA-seq data related to apple dormancy.
• We describe a gene regulatory network (GRN) formed by MdSVPa-containing complexes, which regulate the dormancy cycle in response to environmental cues and hormonal signaling pathways. Additionally, novel molecular evidence regarding the evolutionary functional segregation between DAM and SVP proteins in the Rosaceae is presented.
• MdSVPa sequentially forms complexes with the MADS TFs that predominate at each dormancy phase, altering its DNA-binding specificity and, therefore, the transcriptional regulation of its target genes.

中文翻译：

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揭示 MADS 转录因子复合物在苹果树休眠中的作用

• 一组 MADS 转录因子 (TF) 被认为可以控制温度介导的芽休眠。这些转录因子被称为休眠相关的 MADS-BOX (DAM)，由与拟南芥中的SHORT VEGETATIVE PHASE ( SVP ) 相似的基因编码。MADS 蛋白形成转录复合物，其组合组成决定了它们的分子功能。然而，MADS 多聚体复合物如何控制树木的休眠周期尚不清楚。
• Apple MdDAM 和其他与休眠相关的 MADS 蛋白与 MdSVPa 形成复合物，这对于转录复合物与 DNA 结合的能力至关重要。进行序列 DNA 亲和纯化测序 (seq-DAP-seq) 以鉴定苹果 MADS TF 复合物的全基因组结合位点。通过将 seq-DAP-seq 数据与使用糖皮质激素受体融合系统获得的转录组学数据集以及与苹果休眠相关的 RNA-seq 数据相结合，确定了与结合位点相关的靶基因。
• 我们描述了一个由含有 MdSVPa 的复合物形成的基因调控网络 (GRN)，它根据环境线索和激素信号通路调节休眠周期。此外，还提出了有关蔷薇科 DAM 和 SVP 蛋白之间进化功能分离的新分子证据。
• MdSVPa 与在每个休眠期占主导地位的 MADS TF 依次形成复合物，从而改变其 DNA 结合特异性，从而改变其靶基因的转录调控。