Date Thesis Awarded
Bachelors of Science (BS)
To acquire motility, Caenorhabditis elegans sperm must undergo the
regulated cellular remodeling process of sperm activation, but in the complete
absence of new protein synthesis. Nematode sperm utilize two general
mechanisms to overcome this obstacle: 1) They pre-package many proteins
involved in this remodeling and subsequent sperm motility within the unique
Fibrous Body-Membranous Organelle (FB-MOs) complexes; 2) They employ
large numbers of protein kinases and phosphatases, including SPE-6, in the
acquisition and regulation of motility. Genetically, spe-6 is represented by two
classes of alleles. In null alleles, spermatocytes fail to assemble FB-MOs or
complete their meiotic divisions. In a second class of special alleles,
spermatocytes complete their meiotic divisions, but mutant sperm activate
precociously in the absence of proper extracellular signals.
In this study, we contextualize SPE-6 evolutionarily by demonstrating that
SPE-6 is closest in sequence homology to Tau Tubulin Kinases and that SPE-6
itself is highly conserved throughout Nematoda. We then report the first
description of the dynamic sub-cellular localization pattern of SPE-6 and how this
pattern changes at key steps of C. elegans sperm development. Specifically,
SPE-6 localization dramatically shifts during disassembly of FB-MOs and during
sperm activation. Furthermore, we characterize spe-6 sperm activation alleles at
the protein and phenotypic level to determine that mis-localization or partial loss
of SPE-6 expression is sufficient to induce precocious sperm activation. We
further examine SPE-6 localization under a number of genetic, pharmacological,
and physiological conditions and reveal that SPE-6 localization is context
dependent in activated sperm. Finally, we demonstrate that SPE-6 localization
changes during sperm activation correlate to a change in phosphorylation state.
Peterson, Jackson J., "Genetic and Cytological Analysis of SPE-6, a C. elegans Tau Tubulin Kinase" (2015). Undergraduate Honors Theses. Paper 195.
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