Submission Date

7-24-2015

Document Type

Paper- Restricted to Campus Access

Department

Biology

Faculty Mentor

Rebecca Lyczak

Comments

Presented during the 17th Annual Summer Fellows Symposium, July 24, 2015 at Ursinus College.

Supported by a National Institutes of Health Academic Research Enhancement Award (AREA) grant (1 R15 GM110614-01).

Project Description

Polarity establishment is vital to a diversity of cells including epithelial cells, lymphocytes, and neurons, all of which must polarize to function properly. In C. elegans, polarization of the one-cell embryo determines the anterior-posterior, or head-to-tail axis of the organism. It is known that the sperm-donated centrosome is involved in polarity establishment by contacting the to-be posterior cortex, or inner face of the plasma membrane, and initiating a series of changes in the cell to result in an asymmetrical first division. However, the exact mechanism and role of centrosome-cortex interaction remains unclear. PAM-1, a puromycin-sensitive aminopeptidase, is involved in polarization by preventing premature movement of the centrosome from leaving the posterior cortex. In humans, PAM-1 has a homolog called PSA, and studies suggest that PSA is linked to having a role in neurodegenerative diseases such as Huntington’s disease and Alzheimer ’s disease. Previous work has shown that centrosomes in pam-1 mutants mislocalize by spending a significantly shorter duration at the posterior cortex and prematurely departing as compared to wild-type embryos, leading to a failure in polarity establishment. We use confocal microscopy with fluorescent GFP-linked centrosomes to compare the phenotypes of pam-1 mutants and wild-type embryos. We have evidence that the centrosome must maintain contact with the cortex for a specific duration in order to sustain the polarization process. The construction of new strains containing polarity markers in the form of PAR proteins can provide a greater understanding of the developmental significance of polarity establishment applicable to a diversity of organisms.

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