The Role of Rabbit POC1B inSperm Centrioles

Summary
Centrioles are microtubule-based organelles that form the cell's centrosome (the cell's major microtubule
organization center) and cilium (a subcellular compartment involved in both signaling and motility). A somatic
cell typically has two centrioles. During sperm formation in many animals, including humans, the quantity of
many centriolar proteins declines, and the structure of the sperm centrioles are modified. This process is
known as centrosome reduction and was previously thought to result in the degeneration of at least one
centriole in mammals, leaving the sperm with one or no centrioles. In contrast, the Avidor-Reiss lab has
identified a subset of centriolar proteins that are maintained or enriched during sperm formation and
reorganized into a second centriole with an atypical structure in non-murine mammals. The Avidor-Reiss lab
has named this process "centriole remodeling." Evidence from the Avidor-Reiss lab suggests that centriole
remodeling improves sperm functionality by defining sperm movement via regulating its tail-neck-head
coordination. Therefore, identifying the mechanisms and functions of centriole remodeling and its roles in
fertilization and infertility will open new horizons in the field of reproductive biology.
Our long-term research goal is to gain an in-depth understanding of the long-neglected sperm centrioles,
including their formation, maintenance, function, evolution, and, more importantly, their clinical implications.
This project’s objective is to provide the first insights into the sperm’s sperm centriole's functions and uncover
the mechanisms behind its formation. This project's central hypothesis is that POC1B is essential for DC rod
formation and normal function. The specific aims are to (1) To determine DC rod movement during swimming;
(2) To determine the Centriole Remodeling mechanism; (3) To map POC1B interactions with other rod
components. This project innovatively subjects rabbit sperms for close study to achieve the specific aims. To
study them, it uses state-of-the-art microscopy to directly visualize sperm movement and protein reorganization
during centriole remodeling to account for the species-specific tail-neck-head coordination. This research is
original because it is the first to study with a paradigm-shifting hypothesis on the role of sperm centrioles. This
study will advance our understanding of centrioles in general, centriole remodeling mechanisms in particular,
and reveal their roles during sperm formation. Ultimately, the knowledge gained from these studies will inform
research, diagnostics, and treatments for unknown causes of male infertility, spontaneous abortion, and
developmental diseases.
Dr. Avidor-Reiss has over 20 years of experience mentoring undergrad students and has developed a
mentoring paradigm based on student interests, teamwork, and transferable skills. Undergraduate student
research is a central component of this program. The students will be mentored to produce accurate data,
analyze it impartially, present it professionally in conferences, and author papers to disseminate their
discoveries.

Grant Number: 1R15HD110863-01
NIH Institute/Center: NIH
Principal Investigator: Tomer Avidor-Reiss