Molecular-biological studies about the fate of micronuclei: underlying mechanisms and toxicological relevance

关于微核命运的分子生物学研究：潜在机制和毒理学相关性

• 批准号: 329439085
• 负责人: Professor Dr. Henning Hintzsche
• 金额: --
• 依托单位: Institut für Ernährungs- und Lebensmittelwissenschaften (IEL)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/329439085?language=en
• 关键词: Molecular; biological; studies; about; fate

Different types of mutations play a major role in carcinogenesis, e. g. chromosomal mutations, which are characterized by modifications of the chromosome structure. One form of manifested chromosomal mutations are so-called micronuclei that are formed from chromosomal fragments or missegregated chromosomes. The formation of micronuclei has been investigated thoroughly and the underlying mechanisms are well understood. However, it is less clear whether micronuclei persist within the cell or whether there are any specific mechanisms of elimination. In principle, there could be four possibilities: persistence in the cell, degradation, extrusion from the cell or reintegration into the main nucleus. In the previous project, the fate of micronuclei and the relevance for the whole cell was addressed systematically for the first time. In the project now proposed, the underlying mechanisms shall be identified and characterized.In the previous project, a system for live cell microscopy was established. In preliminary tests, suitable experimental conditions were identified, such as micronucleus-inducing substances, concentrations, treatment times, imaging conditions, and evaluation criteria. Cells were followed for 96 hours and evaluated. Overall, most cells persisted without any change. Some micronuclei were reincorporated into the main nucleus. Degradation and extrusion were rare events. Differences between the substances were not observed.In the project proposed here, the underlying mechanisms shall be investigated. To this end, the question whether the content of a micronucleus is responsible for a specific fate will be addressed. In this context, it is of particular interest whether micronuclei contain whole chromosomes or fragments. For the investigation of the degradation of micronuclei, putative dissociation pathways will be analysed, including autophagy and lysosomal degradation. For the analysis of reincorporation and extrusion from the cell, the involvement of structural proteins of the cytoskeleton will be investigated. This will help elucidating the role of the cytoskeleton for the localisation of micronuclei and for their transport to the main nucleus (indicating reincorporation) or to the cell membrane (indicating extrusion).These experiments will help understanding the mechanistic backgrounds of the different fates of micronuclei.

不同类型的突变在癌发生中起主要作用，例如：G.染色体突变，其特征在于染色体结构的修饰。染色体突变的一种表现形式是所谓的微核，它是由染色体片段或错误分离的染色体形成的。已对微核的形成进行了全面研究，并充分了解了其潜在机制。然而，目前尚不清楚微核是否在细胞内持续存在或是否有任何特定的消除机制。原则上，可能有四种可能性：在细胞中持续存在，降解，从细胞中挤出或重新融入主核。在上一个项目中，首次系统地讨论了微核的命运及其与整个细胞的相关性。在现在提出的项目中，将确定和表征潜在的机制。在前一个项目中，建立了一个活细胞显微镜系统。在初步试验中，确定了合适的实验条件，如微核诱导物质、浓度、处理时间、成像条件和评价标准。跟踪细胞96小时并进行评价。总的来说，大多数细胞没有任何变化。一些微核重新并入主核。降解和挤出是罕见事件。在这里提议的项目中，将调查潜在的机制。为此，将讨论微核的含量是否对特定命运负责的问题。在这种情况下，它是特别感兴趣的微核是否包含整个染色体或片段。为了研究微核降解，将分析推定的解离途径，包括自噬和溶酶体降解。为了分析再掺入和从细胞中挤出，将研究细胞骨架结构蛋白的参与。这将有助于阐明细胞骨架在微核定位及其向主核（表明再结合）或细胞膜（表明挤出）运输中的作用，这些实验将有助于理解微核不同命运的机制背景。