Characterization of a diminished zone, devoid of interchromosomal linkage components in mouse embryonic fibroblast cells

Presenter: Catherine Quecan

Presenter Status: Graduate student

Academic Year: 22-23

Semester: Spring

Faculty Mentor: Lisa Hua

Department: Biology

Funding Source/Sponsor: Other

Other Funding Source/Program: NSF

Abstract:
It was recently found that individual homologous chromosomes are segregated from one another, or antipaired, in dividing human and mouse cells (Hua and Mikawa, 2018). The spatial segregation of the homologous pairs formed a haploid chromosome set along the nuclear division, or centrosome, axis (Hua and Mikawa, 2018). The underlying mechanism for the homologous chromosome segregation remains elusive. Recent data from our lab has shown the presence of a diminished zone, devoid of interchromosomal linkage components of DNA satellite sequences, and CENP-B protein between two chromosome sets in human cells (Cai et al, https://www.biorxiv.org/content/10.1101/2023.03.27.534352v1). The diminished zone may regulate the haploid set organization by partitioning the two haploid chromosome sets apart. However, it is unknown whether the diminished zone is evolutionarily preserved in the mouse. To test whether a diminished zone is also present in mouse cells, we conducted DNA Fluorescence In Situ Hybridization (FISH) for DNA satellite sequences, and 3D analysis of high resolution confocal microscopy for mouse embryonic fibroblasts. Our preliminary data shows a diminished zone in mouse metaphase cells between two chromosome sets. The data suggest that the diminished zone may also be evolutionarily preserved in the mouse, and across different cell types. Findings of our project will deepen our understanding of the conservation of genome organization for mice and humans, and provide insight into the fundamental mechanisms of cell biology.