Deciphering genome integrity maintenance using cytogenomics - Project Summary/Abstract Chromosome missegregation leads to aneuploidy and genomic instability—hallmarks of cancer and contributors to reproductive aging. Understanding how centromere sequence composition, structure, and epigenetic background influence chromosome segregation is important for unraveling the molecular origins of genome instability that could promote cancer evolution. Centromeres are specialized chromosomal regions that serve as sites of kinetochore formation and microtubule binding that partition chromosomes into daughter cells during cell division. The Gerton Lab at the Stowers Institute for Medical Research, supported by NCI funding (R01CA266339, Maintaining the integrity of a genome), investigates centromere biology and kinetochore function to uncover the mechanisms driving chromosome missegregation and aneuploidy. As a Research Specialist II in the Gerton lab, I design and implement experimental strategies addressing centromere composition, functional activity, and chromosome dynamics. Our current research investigates how natural variation in human centromeric array size and activity impacts the accuracy of chromosome segregation. Multiple complete telomere- to-telomere human genome assemblies exposed centromeres as some of the most variable regions in the human genome. Centromeres of the same chromosomes can differ between individuals in both size and the epigenetic determinants of kinetochore positioning. We hypothesize that individual sequence and epigenetic pattern variations in human centromeres can alter their interactions with cell division machinery, predisposing individuals to distinct chromosome missegregation events. To test this hypothesis, we are working on mapping the centromeric sequence landscape and associated kinetochore proteins in individual human centromeres, and investigating how these variations impact chromosome segregation in cultured cells and tumor tissues. I utilize cutting-edge genomic and cytogenetic techniques, along with high-resolution microscopy, to measure centromere sizes and the deposition of inner kinetochore proteins. These data are being integrated with genetic and epigenetic information from the Telomere-to-Telomere (T2T) consortium, a global multi-lab initiative focused on generating complete genome assemblies. This collaboration allows our groups to integrate genomic data with cytogenetics, a method we call “cytogenomics”. This information will be used to find the centromere-specific genetic and epigenetic signatures influencing the accuracy of chromosome segregation in both cultured cells and xenograft tumor tissues. Our long-term goal is to develop comprehensive models explaining how centromere sequences and activities contribute to the rise of aneuploidy and to translate these findings into insights relevant to cancer biology. This research is innovative because it leverages the latest information on human centromeric DNA arrays, introduces new models for centromere organization, and employs cutting-edge molecular, genomic, and imaging tools. The proposed work is significant because it addresses fundamental questions about the role of innate centromere variation in genomic alterations, providing insights into cancer biology and aging.
