Abstract：
Light is an essential environmental signal perceived by a broad range of photoreceptors in plants. Among them, the red/far-red light receptor phytochromes function to promote photomorphogenesis, which is critical to the survival of seedlings after seeds germination. The basic-helix-loop-helix transcription factors phytochrome-interacting factors (PIFs) are the pivotal direct downstream components of phytochromes. H2A.Z is a highly conserved histone variant regulating gene transcription, and its incorporation into nucleosomes is catalyzed by SWI2/SNF2-related 1 complex, in which SWI2/SNF2-related 1 complex subunit 6 (SWC6) and actin-related protein 6 (ARP6) serve as core subunits. Here, we show that PIFs physically interact with SWC6 in vitro and in vivo, leading to the disassociation of HY5 from SWC6. SWC6 and ARP6 regulate hypocotyl elongation partly through PIFs in red light. PIFs and SWC6 coregulate the expression of auxin-responsive genes such as IAA6, IAA19, IAA20, and IAA29 and repress H2A.Z deposition at IAA6 and IAA19 in red light. Based on previous studies and our findings, we propose that PIFs inhibit photomorphogenesis, at least in part, through repression of H2A.Z deposition at auxin-responsive genes mediated by the interactions of PIFs with SWC6 and promotion of their expression in red light.
摘要：
光是植物中一系列光感受器所感知的基本环境信号。其中,红/远红光受体植物色素促进光形态发生，这对种子萌发后幼苗的存活至关重要。bHLH转录因子植物色素相互作用因子(PIFs)是植物色素的关键直接下游成分。H2A.Z是一个高度保守的组蛋白变异体调控基因转录，它掺入核小体是由SWR1配合物催化的，其中SWC6和ARP6作为核心亚基。这里,我们表明PIF在体外和体内与SWC6物理相互作用，导致HY5与SWC6分离。SWC6和ARP6在红光下部分通过PIF调节下胚轴伸长。PIF和SWC6共同调节生长素响应基因如IAA6、IAA19、IAA20和IAA29的表达，并抑制H2A。Z在红光下沉积在IAA6和IAA19。根据以前的研究和我们的发现，我们建议PIF抑制光形态发生，至少在某种程度上,通过镇压H2A。PIF与SWC6的相互作用介导的生长素响应基因的Z沉积，并促进其在红光下的表达。
