Search Results (6)

Mammalian fertilization is a complex and highly regulated process that has garnered significant attention, particularly with advancements in assisted reproductive technologies such as in vitro fertilization (IVF). The fusion of egg and sperm involves a sequence of molecular and cellular events, including capacitation, the acrosome reaction, adhesion, and membrane fusion. Critical genetic factors, such as IZUMO1, JUNO (also known as FOLR4), CD9, and several others, have been identified as essential mediators in sperm–egg recognition and membrane fusion. Additionally, glycoproteins such as ZP3 within the zona pellucida are crucial for sperm binding and triggering the acrosome reaction. Recent gene-editing technologies, such as CRISPR/Cas9 and conditional knockout models, have facilitated the functional annotation of genes such as SPAM1 and ADAM family members, further elucidating their roles in capacitation and adhesion. Furthermore, the integration of CRISPR-Cas9 with omics technologies, including transcriptomics, proteomics, and lipidomics, has unlocked new avenues for identifying previously unknown genetic players and pathways involved in fertilization. For instance, transcriptomics can uncover gene expression profiles during gamete maturation, while proteomics identifies key protein interactions critical for processes such as capacitation and the acrosome reaction. Lipidomics adds another dimension by revealing how membrane composition influences gamete fusion. Together, these tools enable the discovery of novel genes, pathways, and molecular mechanisms involved in fertility, providing insights that were previously unattainable. These approaches not only deepen our molecular understanding of fertility mechanisms but also hold promise for refining diagnostic tools and therapeutic interventions for infertility. This review summarizes the current molecular insights into genes orchestrating fertilization and highlights cutting-edge methodologies that propel the field toward novel discoveries. By integrating these findings, this review aims to provide valuable knowledge for clinicians, researchers, and technologists in the field of reproductive biology and assisted reproductive technologies. Full article

In recent years, the awareness that pesticides can have other effects apart from generic toxicity is growing. In particular, several pieces of evidence highlight their influence on human fertility. In this study, we investigated, by a virtual screening approach, the binding between pesticides and proteins present in human gametes or associated with reproduction, in order to identify new interactions that could affect human fertility. To this aim, we prepared ligand (pesticides) and receptor (proteins) 3D structure datasets from online structural databases (such as PubChem and RCSB), and performed a virtual screening analysis using Autodock Vina. In the comparison of the predicted interactions, we found that famoxadone was predicted to bind Cellular Retinol Binding Protein-III in the retinol-binding site with a better minimum energy value of −10.4 Kcal/mol and an RMSD of 3.77 with respect to retinol (−7.1 Kcal/mol). In addition to a similar network of interactions, famoxadone binding is more stabilized by additional hydrophobic patches including L20, V29, A33, F57, L117, and L118 amino acid residues and hydrogen bonds with Y19 and K40. These results support a possible competitive effect of famoxadone on retinol binding with impacts on the ability of developing the cardiac tissue, in accordance with the literature data on zebrafish embryos. Moreover, famoxadone binds, with a minimum energy value between −8.3 and −8.0 Kcal/mol, to the IZUMO Sperm–Egg Fusion Protein, interacting with a network of polar and hydrophobic amino acid residues in the cavity between the 4HB and Ig-like domains. This binding is more stabilized by a predicted hydrogen bond with the N185 residue of the protein. A hindrance in this position can probably affect the conformational change for JUNO binding, avoiding the gamete membrane fusion to form the zygote. This work opens new interesting perspectives of study on the effects of pesticides on fertility, extending the knowledge to other typologies of interaction which can affect different steps of the reproductive process. Full article

Effective wild cat conservation programs with assisted reproductive technologies are being developed in different parts of the world. The flat-headed cat, fishing cat, and Asiatic golden cat are three species among nine wild Felidae in Thailand that are in need of urgent conservation efforts. Here, we assessed routine sperm characteristics and we report the detection of protein biomarkers related to the fertilization process, IZUMO1 and the CRISP family, and apoptotic markers, active or cleaved caspase-3, in semen samples collected from these wild cats. IZUMO1 was located in the equatorial segment of the sperm head, which is the region involved in gamete interaction. The highest levels of IZUMO1 were found in both the sperm pellet and the seminal plasma of the flat-headed cat, as determined by immunoblotting. CRISP2, a sperm–egg fusion assisting protein, and CRISP3 were found in both the sperm pellet and the seminal plasma, and the highest levels were observed in the fishing cat. Positive correlations between certain semen parameters and IZUMO1, CRISP2, and CRISP3 expression were also demonstrated. Cleaved caspase-3 was found in all sperm samples in all three species and was associated with an increase in DNA fragmentation and a decrease in certain semen characteristics such as motility, viability, and intact acrosomes. Our results suggest that the analysis of IZUMO1, the CRISP family, and cleaved caspase-3, along with the routine sperm characteristics, may allow for better success in breeding management in wild Felidae, particularly in the flat-headed cat and the fishing cat. Full article

Sperm–egg fusion is accomplished through the interaction of a specific set of membrane proteins in each gamete: sperm IZUMO1 and oocyte JUNO. Recently, we found that alternative splicing of the Izumo1 gene generates a novel IZUMO1 isoform (IZUMO1_v2). Here, we obtained four mouse lines, having graded different levels of IZUMO1 protein by combining an original IZUMO1 (IZUMO1_v1) knockout with IZUMO1-null (both IZUMO1_v1 and _v2 disrupted) genetic background, in order to determine how the quantity of IZUMO1 influences male fertility. Subsequently, we clarified that the signal intensity from two quantitative assays, western blot and immunostaining analyses with a monoclonal antibody against mouse IZUMO1, were strongly correlated with average litter size. These results suggest that evaluating IZUMO1 protein levels is useful for predicting fecundity, and is a suitable test for male fertility. Full article

The IZUMO1 gene has promising benefits for the national development of novel non-hormonal contraceptives and in the treatments of fertility. Understanding the function of IZUMO1, its mRNA, and protein expression is critical to gain insight into spermatogenesis and promote sperm-egg fusion during reproduction of Datong yak. Therefore, we estimated the IZUMO1 gene expression in different ages of Datong yak by using semi quantitative PCR, qPCR, and western blotting. The results of the qPCR, semi-quantitative PCR and western blotting revealed that the expression level of IZUMO1 mRNA was significantly (p < 0.05) higher in the testis of 30 months and 6 years old followed by 18 and 6 months old Datong yak, respectively. We also predicted secondary and tertiary protein structure of IZUMO1 by using bioinformatics software that the revealed presence of a signal peptide, Izumo domain, immunoglobulin (Ig) like domain, and transmembrane region. Moreover, immunostaining analysis also elucidated that IZUMO1 was more prominent in the testis of 30 months and 6 years old yak, which represented that the IZUMO1 gene expression might be higher during the peak breeding ages (6 to 7 years) of the yak, and play a potential role in spermatogenesis, fertility, and testicular development. Full article

The mechanism of gamete fusion remains largely unknown on a molecular level despite its indisputable significance. Only a few of the molecules required for membrane interaction are known, among them IZUMO1, which is present on sperm, tetraspanin CD9, which is present on the egg, and the newly found oolema protein named Juno. A concept of a large multiprotein complex on both membranes forming fusion machinery has recently emerged. The Juno and IZUMO1, up to present, is the only known extracellular receptor pair in the process of fertilization, thus, facilitating the essential binding of gametes. However, neither IZUMO1 nor Juno appears to be the fusogenic protein. At the same time, the tetraspanin is expected to play a role in organizing the egg membrane order and to interact laterally with other factors. This review summarizes, to present, the known molecules involved in the process of sperm-egg fusion. The complexity and expected redundancy of the involved factors makes the process an intricate and still poorly understood mechanism, which is difficult to comprehend in its full distinction. Full article