Imaging Transzonal Projections in the Cumulus-Oocyte Complexes: challenges and solutions†.

Deep 3D imaging of oocytes shows several difficulties. Their large size, spherical shape causes depth-dependent artefactual shadow in the middle, resulting from refractive index mismatches induced by turbid organelles and lipid droplets. These mismatches lead to optical aberrations, increasing the laser spot size at the confocal pinhole plan and causing significant attenuation of fluorescence intensity making difficult to clearly image fine structures such as the transzonal projections (TZPs) connecting cumulus cells and the oocyte.

Epitranscriptome marks detection and localization of RNA modifying proteins in mammalian ovarian follicles.

Background: Most of the resources that support the early development of the embryo are stored in the oocyte. Clearing of maternal resources and activation of the embryonic genome to produce its own mRNA transcripts marks the maternal-to-embryo transition. Dependence on stored mRNA can last from a few hours to several days, depending on animal species.

Roles of the cumulus-oocyte transzonal network and the Fragile X protein family in oocyte competence.

In Brief: RNA granules travel through the cumulus cell network of transzonal projections which is associated with oocyte developmental competence, and RNA packaging involves RNA-binding proteins of the Fragile X protein family.

Abstract: The determinants of oocyte developmental competence have puzzled scientists for decades. It is known that follicular conditions can nurture the production of a high-quality oocyte, but the underlying mechanisms remain unknown.

Mammalian cumulus-oocyte complex communication: a dialog through long and short distance messaging.

Communications are crucial to ovarian follicle development and to ovulation, and while both folliculogenesis and oogenesis are distinct processes, they share highly interdependent signaling pathways. Signals from distant organs such as the brain must be processed and compartments within the follicle have to be synchronized. The hypothalamic-pituitary-gonadal (HPG) axis relies on long-distance signalling analogous to wireless communication by which data is disseminated in the environment and cells equipped with the appropriate receptors receive and interpret the messages.