Poster abstracts
Poster number 123 submitted by Stella Lai
Love at first bind: rapid evolution of species-specific fertilization in abalone
Stella M. Lai (Ohio State Biochemistry Program), Regina M. Edgington (Department of Chemistry and Biochemistry, The Ohio State University), Alexander S. Ristau (Department of Chemistry and Biochemistry, The Ohio State University), Damien B. Wilburn
Abstract:
Fertilization—the fusion of haploid sperm and egg to form a diploid zygote—is essential for nearly all sexually reproducing organisms, yet the molecular basis of species-specific gamete recognition, binding, and fusion remains poorly understood. This knowledge gap largely persists because gamete recognition proteins evolve rapidly, yielding tremendous diversity among even closely related species. Moreover, they often exhibit intrinsic disorder, conformational flexibility, and weak or transient interactions, limiting the utility of traditional structural and biochemical approaches. Here, we use red abalone (Haliotis rufescens) as a uniquely tractable model system to investigate the molecular architecture of the sperm–egg interface. Using mutational analyses, functional assays, binding measurements, and mass-based approaches, we are characterizing interactions between sperm protein lysin and its egg receptor VERL to define the molecular determinants of species-specific recognition and egg coat dissolution. In parallel, we are using proteomics approaches to identify and quantify additional protein components of the egg coat, a conserved, species-specific barrier that regulates fertilization by preventing polyspermy and enforcing reproductive isolation. Together, our results reveal a modular egg coat architecture: species specificity is determined by lysin–VERL binding, while egg coat dissolution is mediated by distinct downstream interactions, allowing rapid coevolution of gamete recognition proteins without compromising fertilization fidelity. Our findings offer new insights into how molecular interactions at the gamete interface contribute to speciation and further our understanding of how proteins can achieve high functional specificity through weak, transient, and rapidly evolving interactions.
Keywords: fertilization, proteinprotein interactions, cell recognition