Evolution and function of Marchantia BBR/BPC proteins

作为最早的陆生植物之一，雌雄异株地茅中是否已经建立了BBR/BPC蛋白的分子生化功能，并在整个进化过程中得以维持。由于MpBBR1和MpBBR2具有保守的三元结构域结构，可能与MpLHP1形成同源二聚体和异源二聚体。根据我们在拟南芥中同源蛋白的数据，MpLHP1可能会被MpBBR1或MpBBR2招募到含有ga -motif的dna探针上。MpBBR-MpLHP1复合体的协同作用可能会靶向同源基因，因此可能对生殖器官的发育很重要。拟南芥LHP1或类群II BBR/BPC与马地兰LHP1或类群IV BBR/BPC成员之间的异源二聚体形成将揭示在整个陆地植物进化过程中分子功能能力是否得以维持。在我的假设背景下，我将解决以下核心问题：•MpBBR1和MpBBR2是否在体内形成同型二聚体？蛋白质在细胞核内定位在哪里？作为配子体雌雄异株的结果，了解MpBBR1 - MpBBR2同型异源二聚体是否可以在合子中形成是很重要的。•MpBBR1和MpBBR2是否都能与MpLHP1相互作用？这种相互作用是否仅限于核质，就像它们的拟南芥细胞质一样？•拟南芥和地香属植物的同源蛋白能否在体内形成二聚体？•MpBBR1和MpBBR2是否与ga - dna基序结合？如果是这样，那么了解MpLHP1是否可以被MpBBR1或MpBBR2招募到ga -基序是很重要的。•MpBBR1和MpBBR2是否靶向MADS-box基因启动子-与拟南芥同源物相似？

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?