Title: A Role for Notch signaling in Drosophila Spermatogenesis

Abstract: 

The Notch signaling pathway has diverse functions in male and female gonad development. In Drosophila male embryos, Notch specifies hub cell fate in somatic gonadal precursor cells (SGPs), which are important for maintaining germline stem cells and somatic cyst stem cells throughout the lifetime of adult flies. However, a role for Notch signaling in adult males has only started to emerge recently, and we still don’t understand how the Notch pathway functions to regulate spermatogenesis. Notch has been established to be important for the fertility of multiple systems, including mammals, and must be properly regulated for proper spermatogenesis, but the exact mechanism it employs remains unknown. Characterization of how Notch functions in spermatogenesis has the potential to influence the development of fertility treatments. To tease apart the role of Notch signaling in spermatogenesis, we genetically manipulated the pathway to be constitutively active in the somatic cells of the Drosophila testis alone. We hypothesized that this would result in defects in gonad development as well as altered spermatogenesis. Consistent with the previously described role for Notch signaling in hub formation, we observed an increase in hub-like structures upon overexpression of activated Notch. In addition, Notch signaling must be properly regulated in order to have proper somatic cell maturation, which allows for proper germline-soma communication during spermatogenesis. In the germline, proper levels of Notch signaling appear to be important at late stages of spermatogenesis, specifically at the stage of sperm individualization. In order to understand the mechanism of Notch function in spermatogenesis, it is also important that we find Notch target genes and the molecules that it interacts with in this process,. We started to explore the relationship between Notch and Rib, a Bric-á-brac, Tramtrack, Broad complex (BTB) family protein found to be important in gametogenesis. We found that Notch regulates Rib and these molecules may cooperate in a parallel manner to regulate spermatogenesis.

 

Acknowledgements:

I would like to thank all the people who made this thesis possible, starting with my thesis advisor Dr. Jennifer Jemc Mierisch. She took a chance with me from just a phone call and allowed me to join her lab. Her confidence in me and my graduate application is what allowed me to be accepted into the Masters in Biology program in the first place. Dr. M provided me with so much mentorship in my project and my thesis writing, and I learned many skills from her that have shaped me into the kind of scientist I want to be. My Masters program was an especially difficult experience given the global pandemic that took place for most of my time at Loyola, but Dr. M helped me stay both safe and productive. She also always made me feel appreciated and has been extremely supportive in my future career goals. Secondly, I would like to thank Dr. Thomas Sanger, for being a great committee member and professor to me. I appreciate him making the effort to learn all about Drosophila and all the technical jargon that came with that. I would also like to thank Dr. Daniel Cavanaugh, for agreeing to be a committee member to a random person he’d never met before. His vast knowledge of Drosophila and the questions he asked that challenged me to think critically definitely helped shape my thesis. I would also like to thank Loyola University Chicago for providing the funds with which to complete my thesis research. In addition, my position as a Graduate Research Assistant allowed me to fully focus on my thesis work, and not need to work an outside job. I am also very thankful to the Loyola faculty and staff that kept me in check and meeting important deadlines for the Graduate school. A special shout out to Dr. Terry Grande and Audrey Berry for all your help! I am also very thankful to Joe Schluep for all his help and expertise in microscopy.

Finally, I would like to thank my amazing family for making this experience possible and being so incredibly supportive. We are a very close family, so I know it was not easy on them when I moved across the country for two years. My parents, Antonio Soriano Sr. and Maria Isabel Meza, did not always understand what I was actually doing in this program, but they never failed to show me how proud they were of me. They have sacrificed so, so much for my siblings and I, and it is extremely rewarding to accomplish our goals for them. I am also very thankful for my little brother, Antonio Soriano Jr., for being my main motivation to pursue a higher education. Lastly, I would like to give a shoutout to my absolute best friend in the whole world and twin sister, Diana Soriano. I am thankful for her always celebrating my accomplishments and for listening to me go on and on about my research and the random drama I brought upon myself. I am very blessed to have such a loving family, and I can only hope I have made them incredibly proud!

 

 

Vita:

Adrianna Soriano was born and raised in Houston, Texas. Before attending Loyola University Chicago, she attended the University of St. Thomas during her freshman year as a Psychology major. She then transferred to Houston Baptist University, where she ended up earning a Bachelor of Science in Biology in 2018.

While at Loyola, Adrianna worked in the Mierisch Lab, a developmental biology lab where she learned to love the fruit fly system. Adrianna was elected Vice President of the Biology Graduate Student Association on her second year. Additionally, she had the opportunity to present her research at the Midwest Drosophila Conference, the Loyola Biomedical Graduate Student Research Showcase and the 62nd Annual Drosophila Research Conference. Adrianna graduated from Loyola with Summa Cum Laude honors in 2021.

 

Committee Members:

Jennifer Mierisch

Daniel Cavanaugh

Thomas Sanger