Chromosome Haploid Set Segregation at Interphase

Presenter: Breanna Lee

Co-Presenter(s):
Pingping Cai

Presenter Status: Undergraduate student

Academic Year: 20-21

Semester: Spring

Faculty Mentor: Lisa Hua

Department: Biology

Funding Source/Sponsor: Koret Scholars Program

Other Funding Source/Program: NSF, CSUPERB

Screenshot URL: https://drive.google.com/uc?id=1r1DnGSo-gV0wEgV8JeHsAus0SRRkTgVn

Abstract:
 Chromosomes have been shown to non-randomly organize in human cells during mitosis.  Individual haploid chromosome sets (1n) were positioned on either sides of the nuclear division, or centrosome axis. Segregation of maternal and paternal genomes has been shown in the single cell zygote following fertilization within the fly2, nematode3, and mouse4. However, it is unknown whether this parental genome separation is preserved in subsequent divisions. 

To test whether the chromosome organization pattern is present throughout the cell cycle (interphase and mitosis), and is initially determined at fertilization, we utilized novel holo-tomographic microscopy (HTM) to image human umbilical vein endothelial cells6 (HUVECs). HTM allows for high resolution imaging of individual chromosome dynamics throughout the cell cycle in real time5. Unpublished data from our lab showed that up to three pairs of homologous chromosomes can be separated by their partners by a perpendicular plane at interphase. The perpendicular plane divided the nuclear volume into approximately equal halves. Our recent HTM data also shows the distance between chromocenters is maintained during interphase in HUVECs, thus providing additional evidence to suggest haploid set organization is preserved at interphase. Taken together, these data suggest that haploid chromosome set organization may be preserved throughout the cell cycle. These findings will aid in our fundamental understanding of the underlying mechanism of chromosome organization, and its contribution to cellular function and behavior.