Cell Polarity Establishment in the Budding Yeast Saccharomyces Cerevisiae

dc.contributor.advisor

Lew, Daniel

dc.contributor.author

Howell, Audrey

dc.date.accessioned

2009-05-01T18:30:44Z

dc.date.available

2011-07-26T04:30:04Z

dc.date.issued

2009

dc.department

Genetics and Genomics

dc.description.abstract

Establishing an axis of cell polarity is central to cell motility, tissue morphogenesis, and cell proliferation. A highly conserved group of polarity regulators is responsible for organizing a wide variety of polarized morphologies. One of the most widely expressed polarity regulators is the Rho-type GTPase Cdc42. In response to cell cycle cues the budding yeast Saccharomyces cerevisiae polarizes Cdc42p to a discrete site on the cell periphery. GTP-Cdc42p recruits a number of effectors that aid in the organization of a polarized actin cytoskeleton. The polarized actin cytoskeleton acts as tracks to facilitate the delivery of the secretory vesicles that will grow the bud, an essential process for an organism that proliferates by budding. We have employed treatment with the actin depolymerizing drugs Latrunculin A and B as well as high-speed timelapse microscopy of fluorescently labeled polarity proteins to characterize the assembly of the incipient bud site.

Often, ensuring that only a single axis of polarity is established is as important as generating asymmetry in the cell. Even in the absence of positional cues dictating the direction of polarization, many cells are still able to self-organize and establish one, and only one, polarity axis through a process termed symmetry breaking. Symmetry breaking is thought to employ positive feedback to amplify stochastic fluctuations in protein concentration into a larger asymmetry. To test whether singularity could be guaranteed by the amplification mechanism we re-wired yeast to employ a synthetic positive feedback mechanism. The re-wired cells could establish polarity, however they occasionally made two buds simultaneously, suggesting that singularity is guaranteed by the amplification mechanism.

dc.format.extent

2241411 bytes

dc.format.mimetype

application/pdf

dc.identifier.uri

https://hdl.handle.net/10161/1145

dc.language.iso

en_US

dc.subject

Biology, Cell

dc.subject

actin

dc.subject

CDC

dc.subject

polarity

dc.subject

positive feedback

dc.subject

symmetry breaking

dc.subject

yeast

dc.title

Cell Polarity Establishment in the Budding Yeast Saccharomyces Cerevisiae

dc.type

Dissertation

duke.embargo.months

24

Files

Original bundle

Now showing 1 - 1 of 1
Loading...
Thumbnail Image
Name:
D_Howell_Audrey_a_200904.pdf
Size:
2.14 MB
Format:
Adobe Portable Document Format

Collections