The Number of Membranous Organelles in Mutant and Wild Type C. elegans Spermatids Open Access

Phillis, Stephanie Joy (2013)

Permanent URL: https://etd.library.emory.edu/concern/etds/z603qx86k?locale=en
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Abstract

During C. elegans spermatogenesis, fibrous body membranous organelles (FB-MOs) are present through the developmental progression from syncytial pachytene spermatocytes to spermatids (L'Hernault, 2009). FB-MOs contain major sperm protein, which is required for spermatozoan motility, plus other proteins needed for successful fertilization, making them a crucial part of functional sperm development. FB-MOs consist of three major parts, a membranous organelle (MO) head, a collar region separating the MO head from the fibrous body, and a fibrous body (FB) that contains major sperm protein filaments. In developing spermatids, the FB compartment disassembles releasing depolymerized major sperm protein dimers into the spermatid cytoplasm. After FB disassembly, the MO assumes a position beneath the plasma membrane. During spermiogenesis (the transition of a spermatid into a spermatozoon) the head fuses with the spermatozoonplasma membrane, releasing its contents and creating permanent fusion pores. The exact influence that FB-MOs have on the asymmetrical divisions of spermatogenesis and the development of fertilization competence by sperm is still incompletely understood. My thesis uses a vital staining technique to examine MO number and physiology and whether it is affected in various diverse spermatogenesis-defective (spe) mutants. This vital staining technique requires that MOs have a function vacuolar (V-) ATPase to become acidified, so my work showed that certain mutants with defective MO structure had competent V-ATPase activity. Additionally, I correlated MO number and position was correlated with spermatid volume. I found that spermatid volume varies under certain conditions but that the number of MOs seems to scale with cell volume, suggesting that spermatids can "count" organelles. In the future, the mutant survey I initiated should be more widely applied as it seems to offer a robust way to identify defects in MO physiology and/or numerical/volume ratios.

Table of Contents

1. INTRODUCTION p. 1

2. REPRODUCTIVE ANATOMY OF THE HERMAPHRODITE p. 2

3. REPRODUCTIVE ANATOMY OF THE MALE p.3

4. SPERMATOGENESIS p.4 5. FB-MOs p.8 6. SPERMIOGENESIS p.10 7. FERTILIZATION p.12

8. PROJECT OVERVIEW AND GENOTYPES OF INTEREST p.13

spe-8 p.15 spe-10 p.16 spe-21 p.17 spe-42 p.17 fer-14 p.18 peel-1 p.19

him-5 & him-8 p.19

fem-3 p.20

9. MATERIALS AND METHODS p.22

10. RESULTS p.24

11. DISCUSSION AND CONCLUSIONS p.30

REFERENCES p.36

APPENDIX 1: RAW DATA p.40

TABLES AND FIGURES

TABLE 1: SUMMARY OF THE MAJOR PHENOTYPIC CHARACTERISTICS FOR THE GENOTYPES OF INTEREST p.21

TABLE 2: RESULTS SUMMARY p.27

TABLE 3: RAW DATA p.40

FIGURE 1: SPERMATOGENESIS AND FB-MO SUMMARY p.8

FIGURE 2: CONTROL IMAGES p.28

FIGURE 3: peel-1 IMAGES p. 28

FIGURE 4: MUTANT IMAGES p.29

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