Characterization of Interchromosomal DNA Tethers

Presenter: Christian Casas

Co-Presenter(s):
Marissa Cerros

Presenter Status: Graduate student

Academic Year: 20-21

Semester: Spring

Faculty Mentor: Lisa Hua

Department: Biology

Funding Source/Sponsor: Koret Scholars Program, LSAMP, Other

Other Funding Source/Program: SUG, Forest W and Ida J Benson Scholarship, NSF, CSUPERB

Screenshot URL: https://drive.google.com/uc?id=1P8rGga9qac8Pbj1brxWtlkQ2NzH2CHcE

Abstract:
It was recently discovered that homologous chromosomes are spatially segregated, or antipaired, during mitosis. A haploid chromosome set was found to segregate along the nuclear division axis. Previous data have shown the presence of DNA tethers between chromosomes. However, it is unknown whether these DNA tethers regulate haploid set organization. These DNA tethers consist of pericentromeric satellite DNA, repetitive tandem repeat sequences within the heterochromatin that surrounds the centromere region of each individual chromosome, and an associated protein, Centromere Protein B (CENP-B). We hypothesize that these DNA interchromosomal tethers, and CENP-B, collectively regulate haploid chromosome organization by ensuring that the haploid sets remain in their respective nuclear hemisphere throughout mitosis. We will characterize the presence of these DNA tethers specifically within each haploid chromosome set, and their absence between haploid sets in human umbilical vein endothelial cells (HUVECs) using DNA fluorescence in situ hybridization (FISH), immunofluorescence (IF), and 3D analysis of high-resolution confocal microscopy. Outcomes of our findings will contribute to the understanding of genome organization and fundamental mechanisms of cell biology.