Actin brings chromosomes up to speed during oocyte maturation

Intersectin-Cdc42 interaction is required for orderly meiosis in porcine oocytes

Intersectins (ITSNs) have been shown to act as adaptor proteins that govern multiple cellular events via regulating Cdc42 activity. However, it remains to be determined whether the ITSN-Cdc42 pathway is functional in porcine oocytes. To address this question, we used a small molecule, ZCL278, to selectively disrupt the ITSN2-Cdc42 interaction. In the present study, we find that porcine oocytes exposed to ZCL278 are unable to completely progress through meiosis. Meanwhile, the spindle defects and chromosomal congression failure are frequently detected in these oocytes. In support of this, we observed the accumulated distribution of vesicle-like ITSN2 signals around the chromosome/spindle region during porcine oocyte maturation. In addition, our results also showed that inhibition of the ITSN-Cdc42 interaction impairs the actin polymerization in porcine oocytes. In summary, the findings support a model where ITSNs, through the interaction with Cdc42, modulates the assembly of meiotic apparatus and actin polymerization, consequently ensuring the orderly meiotic progression during porcine oocyte maturation.

Emerging roles for nucleoporins in reproductive cellular physiology 1

Nucleoporins are a specialized subset of nuclear proteins that comprise the nuclear pore complex and regulate nucleocytoplasmic transport. Recent demonstrations of roles for individual nucleoporins in multiple paradigms of differentiation via mechanisms independent of nuclear trafficking represent conceptual advances in understanding the contributions of nucleoporins to cellular development. Among these, a functional role for nucleoporins in reproductive fitness and gametogenesis has been identified, supported by robust models and clinical studies that leverage the power of next generation sequencing technology to identify reproductive-disease-associated mutations in specific nucleoporins. Proper nucleoporin function manifests in different ways during oogenesis and spermatogenesis. However, nonhuman models of gametogenesis may not recapitulate human mechanisms, which may confound translational interpretation and relevance. To circumvent these limitations, identification of reproductive pathologies in patients, combined with next generation sequencing approaches and advanced in silico tools, offers a powerful approach to investigate the potential function of nucleoporins in human reproduction. Ultimately, elucidating the role of nucleoporins in reproductive biology will provide opportunities for predictive, diagnostic, and therapeutic strategies to address reproductive disorders.