Degree Type

Honors Capstone Project

Date of Submission

Spring 5-1-2006

Capstone Advisor

Dr. Melissa Pepling

Honors Reader

Dr. Scott Erdman

Capstone Major

Biology

Capstone College

Arts and Science

Audio/Visual Component

no

Capstone Prize Winner

no

Won Capstone Funding

no

Honors Categories

Sciences and Engineering

Subject Categories

Biochemistry | Biochemistry, Biophysics, and Structural Biology

Abstract

During oogenesis in the Drosophila ovary, a 16-cell cyst develops in which one cell grows to become the oocyte. The surrounding nurse cells transport mRNAs, proteins, and organelles to the oocyte during development and must be localized properly within the oocyte. A complex of proteins is responsible for mRNA localization, including the recently discovered protein Trailerhitch. Homologs of Trailerhitch exist in other species including C. elegans, yeast, mice, and humans, but the function is unknown. We are interested in studying the function of Trailerhitch in mouse germ cell development. Mice with a nonfunctional Trailerhitch gene were synthesized using a gene trapping method in which a β-geo vector was inserted randomly into the intron between exons two and three of the Trailerhitch gene. The coding sequence of the gene was thus interrupted and inactivated. The mutation was then transmitted through the germline of mice in order to analyze the effects. Using Western blotting, β- galactosidase staining, and Whole Mount Antibody staining, we have determined that Trailerhitch is expressed in both ovaries and testes of mice at all ages. In neonatal ovaries, Trailerhitch is expressed in the cytoplasm of oocytes and is highly concentrated in the Golgi. In neonatal testes, Trailerhitch is widely expressed in the cytoplasm of spermatagonia. However, Trailerhitch is expressed only in a concentrated region of the cytoplasm of spermatocytes in adult testes, which is thought to be the chromatoid body. During development, Trailerhitch is expressed widely throughout the embryo, which was determined by performing β- galactosidase staining during ages 7.5 dpc – 13.5 dpc. Trailerhitch expression in other organ systems of the mouse signifies that Trailerhitch may have a more general cellular function. Using PCR primer walking, we have identified the exact base pair location of the β-geo insertion. This discovery has allowed us to distinguish between heterozygous and homozygous mutants. According to genotyping, RT-PCR, and Western blot data, it appears that homozygous mutants are embryonic lethal prior to the age of 7.5 dpc (days post coitum). This finding must be confirmed and the exact age of lethality must be determined.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.

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Biochemistry Commons

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