The biological role of interferon y induced 65 kDa GBPs as effector molecules in host defense

干扰素γ（IFNγ）是一种促炎细胞因子，在感染的遏制和清除中起着至关重要的作用。IFNγ激活的许多基因的表达使应答细胞能够建立有效的抗微生物效应子系统，导致成功的病原体消除或复制抑制。迄今为止，IFNγ诱导的一些效应分子已被表征;然而，对IFNγ介导的效应细胞的抗微生物应答的理解在很大程度上仍不完整。特别是65 kDa鸟苷酸结合蛋白（GBP）被IFNγ大量诱导，但其功能仍然是个谜。在我们最近的研究中，我们可以鉴定出mGBP家族的6个新成员（mGBP 6，-7，-8，-9，-10和-11）。我们可以确定mGBP家族的所有11个成员都可以被IFNγ诱导，并且在感染L.单核细胞增多症和T.刚地。值得注意的是，几个mGBP（mGBP 1，-2，-3，-6，-7，和-9）显示了亚细胞重新分布和直接共定位与寄生空泡后，主动入侵T。弓形虫核苷酸结合基序的突变导致蛋白质在未感染细胞中的异常定位，并导致重新定位到细胞内病原体的能力显著降低。在最后一个资助期内，成功产生了几种mGBPs（mGBP 1、mGBP 2、mGBP 3和mGBP 5）的基因缺陷小鼠。这些小鼠系是可行的，将用于鉴定单个mGPB的非冗余功能。我们已经可以证明，mGBP 1-/-胚胎成纤维细胞表现出显着降低的能力，以抑制细胞内的T.刚地氏菌的复制。此外，mGBP 6、-7、-8、-9和-10的基因靶向正在进行中，本文提出了3号和5号染色体上mGBP基因簇的化合物靶向。拟议项目的目的是表征mGBP蛋白对不同病原体的分子效应及其在防御细菌，病毒和寄生虫感染中的体内作用。

Interferon γ (IFNγ) is a proinflammatory cytokine which plays a crucial role in the containment and clearance of infections. The IFNγ activated expression of numerous genes enables responsive cells to establish potent antimicrobial effector systems, leading to successful pathogen elimination or inhibition of replication. Some effector molecules induced by IFNγ have been characterized so far; however, the understanding of the IFNγ mediated antimicrobial response of effector cells is still largely incomplete. In particular, the 65 kDa guanylate-binding proteins (GBPs) are abundantly induced by IFNγ, but their functions are still enigmatic. In our recent studies, we could identify 6 novel members of the mGBP family (mGBP 6, -7, -8, -9, -10, and -11). We could establish that all 11 members of the mGBP family are inducible by IFNγ and are rapidly induced in mice after infection with L. monocytogenes and T. gondii. Remarkably, several mGBPs (mGBP 1, -2, -3, -6, -7, and -9) show a subcellular redistribution and direct colocalization with the parasitophorous vacuole after active invasion of T. gondii parasites. Mutations of the nucleotide binding motifs lead to an aberrant localization of the proteins in uninfected cells and to a dramatically reduced capability to relocalize to intracellular pathogens. During the last funding period gene-deficient mice for several mGBPs (mGBP1, -2, -3, and 5) were successfully generated. These mouse lines are viable and will be employed to identify non-redundant functions of individual mGPBs. We could already demonstrate that mGBP1-/- embryonic fibroblasts show a significantly reduced capability to restrain the intracellular replication of T.gondii. Furthermore, gene targeting of mGBP 6, -7, -8, -9, and -10 is ongoing and the compound targeting of the mGBP gene clusters on chromosomes 3 and 5 are proposed here. The aim of the proposed project is the characterization of the molecular effects of the mGBP proteins on diverse pathogens and their in vivo role in the defence against bacterial, viral, and parasitic infections.