Stowers Institute Researchers Discover Unexpected Flexibility in Meiotic Protein Machinery
Researchers at the Stowers Institute for Medical Research published a new study in Science Advances revealing that the molecular machinery governing meiosis is more widely shared across animals and more flexible than previously understood. According to the study published under DOI 10.1126/sciadv.aei0758, familiar-looking proteins and protein complexes do not always perform identical jobs across different species, challenging long-held assumptions about reproductive biology.
Meiosis is the tightly choreographed process where egg and sperm cells divide, allowing chromosomes to find their partners and exchange genetic material. When disruptions occur during this cellular division, the consequences can include infertility, miscarriage, and birth defects. Traditional functional studies of the proteins coordinating this process have largely been limited to model organisms like mice, fruit flies, and roundworms.
Sea Anemone Genetics Reveal Diverging Protein Functions
The research project was led by Stefanie Williams, a former Stowers Graduate School doctoral student currently working as a postdoctoral fellow at the European Molecular Biology Laboratory. The work emerged from a collaboration between the laboratory of Stowers Investigator and Graduate School President Matt Gibson and the laboratory of the late R. Scott Hawley, who served as a Stowers Investigator and pioneer in the field of meiosis.
Williams examined the sea anemone Nematostella vectensis, a relative of corals and jellyfish, to understand how its meiotic machinery operates. She discovered that the sea anemone assembles a ladder-like structure known as the synaptonemal complex between paired chromosomes, much like humans do. This structure contains eight of the ten proteins recognized to make up the human synaptonemal complex.
However, when Williams tested the actual functions of those proteins, the similarities broke down. “Despite their essential function, many of the proteins that coordinate meiosis show signatures of rapid evolution, changing much faster than normal housekeeping genes do,” Williams said. When she disabled three of these proteins in the sea anemone, mutations in two genes—sycp1 and syce2—resulted in female sterility, while males carrying identical mutations remained fertile.
“When I first sat at the microscope and saw that some components are not required to synapse chromosomes, I thought I must have made a mistake because it didn’t make any sense,” Williams said. “Finding out that the architectural functions of synaptonemal complex proteins must have changed was totally unexpected.”
Live Imaging Capabilities Open New Research Avenues
The choice of Nematostella as an experimental model offers distinct advantages over traditional mammalian systems. Because the sea anemone is transparent and features eight gonads that can be observed directly in living animals, researchers gain the ability to watch meiosis unfold in real time within living tissue.
“This work establishes Nematostella as a good experimental system for understanding meiotic processes at a deeper level,” Gibson stated. “The potential for live imaging could reveal new biology that’s difficult to observe in mammals, particularly at the cellular level.”
Gibson noted that Williams’ trajectory from rotating in the Hawley Lab to exploring sea anemones in the Gibson Lab bridged two distinct fields. “Scott inspired Steffi’s passion for meiosis,” Gibson said. Williams reflected on that mentorship, noting that Hawley taught her to follow her scientific curiosity regardless of conventional expectations.
Frequently Asked Questions About the Stowers Institute Meiosis Study
Why is the sea anemone used instead of mice or fruit flies for this study?
Nematostella vectensis is transparent and possesses eight gonads that can be observed directly in live specimens. This transparency allows researchers to watch meiosis unfold in living tissue, an advantage that is difficult or impossible to achieve in traditional mammalian models like mice.
Which specific proteins caused unexpected results when disabled?
Stefanie Williams disabled three homologous proteins, finding that mutations in sycp1 and syce2 led to female sterility while leaving males fertile. Furthermore, the loss of syce2 disrupted the stabilization of paired chromosomes exclusively in females.
Where was the research published and who funded the collaboration?
The findings were published in the journal Science Advances. The project originated from a collaborative effort between the Gibson laboratory and the laboratory of the late R. Scott Hawley at the Stowers Institute for Medical Research.