Computer Algebra

我们的研究计划的目标是研究与细菌II组内含子相关的剪接、功能和进化问题。在第一个倡议中，我们研究了第二组内含子的反式剪接，以解决第二组内含子、核内含子和作为剪接机制一部分的五个小RNA(剪接体)之间的进化关系。其次，我们正在探索细菌细胞中第二组内含子的各种剪接途径。最后，我们研究了这些反向移动元件通过接合和转导在细菌物种之间的传播。我们的模式系统是来自乳酸乳球菌的Ll.LtrB第二组内含子。乳酸乳杆菌是一种重要的低G+C革兰氏阳性菌，主要用于乳制品工业中奶酪和酸奶的生产。在乳酸乳杆菌中，LtrB与不同的结合元件：pRS01和pAH90以及染色体性别因子相关。因此，我们正在研究乳酸乳杆菌性别因子在细菌细胞之间通过接合转移是否能够支持其所传递的Ll.LtrB内含子的传播。我们还研究了Ll.LtrB内含子是否可以通过各种噬菌体(转导)在细菌王国中传播。在将乳酸乳杆菌的内含子携带元件转移到不同的细菌物种后，我们将研究Ll.LtrB移动第二组内含子在其新的细胞环境中的重新插入。Ll.LtrB内含子在同源和非同源位点的重新插入将被研究。我们还在研究细菌细胞中第二组内含子的各种剪接途径，以及它们被片段并仍以反式剪接的能力。这将使我们能够解决核内含子的起源及其剪接机制。

The goal of our research program is to study splicing, function and evolutionary questions related to bacterial group II introns. In a first initiative we study trans-splicing of group II introns in order to address the evolutionary relationships between group II introns, nuclear introns and the five small RNAs that are part of the splicing machinery, the spliceosome. Secondly, we are exploring the various splicing pathways of group II introns in bacterial cells. Finally, we study the dissemination of these retromobile elements by conjugation and transduction between bacterial species. Our model system is the Ll.LtrB group II intron from Lactococcus lactis. L. lactis is an industrially important low G+C Gram-positive bacterium mainly used in the dairy industry for the production of cheese and yogurt. Ll.LtrB was found associated with different conjugative elements in L. lactis: the pRS01 and pAH90 plasmids and the chromosomal sex factor. We are thus studying if the transfer by conjugation of the L. lactis sex factor between bacterial cells can support the spread of the Ll.LtrB intron it conveys. We also study if the Ll.LtrB intron can be disseminated in the bacterial kingdom by various bacteriophages (transduction). After transfer of the intron-carrying elements from L. lactis to different bacterial species, we will study the reinsertion of the Ll.LtrB mobile group II intron in its new cell environment. Reinsertion of the Ll.LtrB intron into homologous and non-homologous sites will be studied. We are also studying the various splicing pathways of group II introns in bacterial cells and their capacity to be fragmented and still splice in trans. This will allow us to address the origin of nuclear introns and their splicing machinery.