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Author ORCID Identifier

https://orcid.org/0000-0001-8451-2617

AccessType

Campus-Only Access for Five (5) Years

Document Type

dissertation

Degree Name

Doctor of Philosophy (PhD)

Degree Program

Animal Biotechnology & Biomedical Sciences

Year Degree Awarded

2022

Month Degree Awarded

September

First Advisor

Pablo E. Visconti

Second Advisor

Maria Gracia Gervasi

Third Advisor

Rafael Fissore

Fourth Advisor

Jesse Mager

Fifth Advisor

Juan Jimenez

Subject Categories

Cell Biology | Developmental Biology | Other Cell and Developmental Biology

Abstract

Male reproduction is dynamic cascade of events in which a stem cell undergoes several steps of differentiation and morphogenesis to produce a viable sperm cell during spermatogenesis. However, the newly formed sperm is still unable to fertilize and is immotile. Uniquely, sperm are both transcriptionally and translationally silent, therefore, in order to undergo molecular changes rendering the sperm capable of fertilization, they rely on post-translational modifications. The complex cellular dynamics of the epididymis as well as the length of time required for sperm to undergo sperm maturation has made investigating changes occurring during maturation challenging. Researchers have focused on recovering sperm from specific epididymal regions to compare molecular events. However, while it provides momentary differences, we may still be missing key regulators of the acquisition motility and fertilization capabilities. Nevertheless, post-maturation events during sperm capacitation have been very well documented, and due to our advancements in understanding the generation of assisted reproductive technologies (ART) has improved our ability to overcome infertility.

However, while advances have been made in improving ART protocols, like

enhancements towards in vitro fertilization (IVF), major limitations still occur reducing the overall efficiency. Some groups have made efforts to reduce the limiting factors by improving sperm selection techniques, which suggests a more significant role the sperm contribution aside from the paternal genome and activation of the oocyte by the sperm-specific factor, PLCz. Recent studies have revealed specific populations of small RNA contributions delivered to sperm during sperm maturation are contribute to embryo development. Specifically, when immature sperm were used with an isolated population of small RNAs from the mature sperm region, embryo development was improved. This data suggested that having a more complete understanding of both sperm maturation and the contribution of sperm on embryo development can improve our ability to overcome limiting factors observed in ART.

The goal of this dissertation is to characterize an undescribed post-translational modification as it pertains to the acquisition of sperm motility and sperm maturation. Additionally, to investigate the role of mature sperm after fertilization and how changes to preincubation conditions can influence the success of pre-implantation development. Hence, the understanding the contributions of sperm after fertilization as occurred will provide pivotal insights into the mechanisms that regulate early pre-implantation development. Ultimately the goal is to use this knowledge to aid in the treatment of male infertility in human, in addition to enhancing the reproduction of high-value animals like livestock species, endangered animal preservation and transgenic animal production.

DOI

https://doi.org/10.7275/30805801

Available for download on Friday, September 01, 2023

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