Toward understanding the function of the G2 phase in the mammalian somatic cell cycle - Moskaleva, Alisa; Ferrell, James Ellsworth; Cimprich, Karlene; Meyer, Tobias; Stearns, Tim; Stanford University, Department of Chemical and Systems Biology (2015)
This thesis contains studies on the G2 phase of the cell cycle, which is arguably the most mysterious aspect of how cells prepare for cell division. Chapter 1 gives a historical overview of research on G2 and introduces key concepts and molecular players. G2 phase differs across model systems. It is absent in budding yeast as well as the early embryos of Xenopus and Drosophila. It is particularly well-understood in later embryonic development of Drosophila and in fission yeast, where an important regulator is mitotic phosphatase Cdc25. In mammalian tissue culture cells, the model system that is closest to cells of the human body, both Cdc25 and RCC1, a protein that emerged out of the analysis of mammalian cell-cycle mutants, present tantalizing possibilities for how the G2 phase may be regulated, but many unanswered questions remain. Chapter 2 presents results on how the duration of G2 phase affects mitotic progression, in particular the timeliness of anaphase. This work uses MCF10A cells that express fluorescently tagged PCNA, a marker of DNA replication, and fluorescently tagged histone H2B, a marker of DNA morphology, in live-cell microscopy to directly measure durations of all cell-cycle phases. G2 phase is then shortened by PD0166285, a drug known to induce premature mitosis. Shortening G2 phase results in a prolonged interval from nuclear envelope breakdown to anaphase that is partially rescued by inhibiting the spindle assembly checkpoint and not affected by inhibiting protein synthesis. Chapter 3 presents possible future directions for these studies. It contains preliminary data on the effect of shortened G2 on microtubule-kinetochore attachment, repair of DNA damage, and the centrosome.
Submitted to the Department of Chemical and Systems Biology.
Thesis (Ph.D.)--Stanford University, 2015.
Rights: (c) Copyright 2015 by Alisa Moskaleva
Rights: This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
Keywords: theses