拟南芥RPT2与RIP1互作调节下胚轴向光弯曲的功能鉴定

拟南芥突变体rpt2-2表型类似于蓝光受体双突变体phot1 phot2, 缺失强蓝光诱导的下胚轴向光弯曲, 不同于双突变体phot1 rpt2-2下胚轴向光性正常, 表明在RPT2上游存在受PHOT1抑制的旁路调节途径。本文以RPT2为诱饵蛋白进行酵母文库筛选, 成功筛选到包括JAC1 和PHOT1在内的6个与RPT2互作的蛋白(RIPs, RPT2 Interacting Proteins)。酵母互作验证显示, 其中有4个蛋白可以与RPT2相互作用。表型分析显示基因RIP1对应的2个突变体rip1-1和rip1-2, 发现rip1-1和rip1-2单突变体下胚轴向光弯曲正常, 而rpt2-2 rip1-1和rpt2-2 rip1-2双突变体表型类似于phot1 rpt2-2双突变体, 恢复拟南芥下胚轴向光弯曲反应, 暗示RIP1蛋白可能调节PHOT1介导强蓝光抑制反应, 分析鉴定蛋白RIP1的生物学功能将有助于揭示PHOT1介导强蓝光抑制反应的机制。

Functional Analysis of Hypocotyl Phototropism Modulated by RPT2-Interacting Protein RIP1 in Arabidopsis thaliana L.

The rpt2-2 single mutant lost phototropism, but phot1 rpt2-2 double mutant shows phototropic response, indicating that PHOT1 has a function in inhibiting hypocotyl phototropism, and RPT2 maybe play vital role in these prosses. Here, we used RPT2 as bait protein to screen yeast library and successfully obtained six proteins interacted with RPT2 including JAC1 and PHOT1. Yeast hybridization verified that four of these proteins could interact with RPT2. Phenotypic analysis of two mutants of gene RIP1 showed that the single mutant rip1-1 and rip1-2 had normal phototropism in response to high blue light, but rpt2-2 rip1-1 and rpt2-2 rip1-2 double mutant were defective in phototropism, similar with the phot1 rpt2-2 double mutant. These results suggested that this protein may modulate PHOT1-mediated high blue light inhibitory response. Functional analysis of this protein will be helpful to promote the discovery of the mechanism of phot1-mediated inhibitory response.