Evolution and function of Marchantia BBR/BPC proteins

本研究的目的是探讨BBR/BPC蛋白的分子生物学功能是否已经在地钱中确立并在进化过程中得以保持，由于地钱MpBBR 1和MpBBR 2保守的三部分结构域，可能与MpLHP 1形成同源二聚体和异源二聚体。根据我们在拟南芥中的正向同源蛋白的数据，MpLHP 1可能被MpBBR 1或MpBBR 2募集到含有GAGA基序的DNA探针上。MpBBR-MpLHP 1复合物的协同作用可能靶向同源异型基因，因此可能对生殖器官的发育很重要。拟南芥LHP 1或第II组BBR/BPC与地钱LHP 1或第IV组BBR/BPC之间的跨物种异源二聚体形成将揭示分子功能能力是否在陆地植物进化过程中得以保持。 MpBBR 1和MpBBR 2在体内形成同源二聚体吗？这些蛋白质在细胞核内的什么位置？由于配子体的异二聚体，了解MpBBR 1-MpBBR 2同型异二聚体是否能在合子中形成是很重要的。· MpBBR 1和MpBBR 2都能与MpLHP 1相互作用吗？这种相互作用是否仅限于核质，类似于他们的拟南芥同源物？ 拟南芥和地钱中的正向同源蛋白能在体内形成二聚体吗？ MpBBR 1和MpBBR 2是否与GAGA-DNA基序结合？如果是这样的话，了解MpLHP 1是否可以被MpBBR 1或MpBBR 2募集到GAGA基序中是很重要的。 MpBBR 1和MpBBR 2靶向MADS盒基因启动子-与它们的拟南芥直向同源物相似吗？

This short term project addresses the question whether the molecular biochemical functions of BBR/BPC proteins were already established in the dioecious liverwort Marchantia, as one of the earliest land plants, and maintained throughout evolution, or not.Because of the conserved tripartide domain structure, it might be possible that Marchantia MpBBR1 and MpBBR2 can form homodimers and heterodimers with MpLHP1. Based on our data from the orthologous proteins in Arabidopsis, it might be possible that MpLHP1 can be recruited by MpBBR1 or MpBBR2 to GAGA-motif containing DNA-probes. The concerted action of the MpBBR-MpLHP1 complex will presumably target homeotic genes and, hence, might be important for the development of reproductive organs. Cross-species heterodimer formation between Arabidopsis LHP1 or group II BBR/BPCs and Marchantia LHP1 or group IV BBR/BPC members will disclose whether the molecular functional capacities were maintained throughout land plant evolution.Against the background of my hypotheses, I will address the following central questions:• Are MpBBR1 and MpBBR2 forming homodimers in vivo? Where do the proteins localize inside the nucleus? As a consequence of gametophytic dioecy, it is important to know whether MpBBR1 - MpBBR2 homotypic heterodimers can form in the zygote.• Are both MpBBR1 and MpBBR2 able to interact with MpLHP1? Is this interaction restricted to the nucleoplasm, similar to their Arabidopsis othologs?• Are orthologous proteins from Arabidopsis and Marchantia able to form dimers in vivo?• Are MpBBR1 and MpBBR2 binding to GAGA-DNA-motifs? If so, it is important to know whether MpLHP1 can be recruited by MpBBR1 or MpBBR2 to GAGA-motifs.• Are MpBBR1 and MpBBR2 targeting MADS-box gene promoters - similar to their Arabidopsis orthologs?