bims-cebooc 2024-12-01 papers

Issue of 2024–12–01
three papers selected by
Gabriele Zaffagnini, Universität zu Köln

Methods Mol Biol. 2025 ;2874 99-114

Using FRET to Define Cdk1-Dependent Ordering of Events During Exit from Second Meiotic M-Phase in Oocytes.

Exit from M-phase requires a precise sequence of molecular events for successful completion, with errors in the process resulting in cell death or aneuploidy, a characteristic feature of cancer and the leading cause of pregnancy failure. Exit from the second meiotic division (MII) in oocytes is a unique event triggered by sperm, involving female anaphase II as well as both male and female pronuclear formation. Very little is known about how these events involving two distinct cell types are coordinated. M-phase exit is driven by inactivation of the master cell-cycle regulator, cyclin-dependent kinase 1 (Cdk1), but details of how Cdk1 orchestrates MII exit has remained sketchy due to technical challenges in studying these events. Here we detail a protocol for undertaking in-depth analysis of Cdk1 activity throughout fertilization in live mouse oocytes using a Cdk1 Fluorescence Resonance Energy Transfer (FRET) biosensor. This protocol illustrates the utility of time-lapse imaging and FRET for interrogating experimentally challenging cell-cycle events.

Keywords: Cdk1; FRET; Fertilization; M-phase exit; Meiosis; Pronuclear formation

DOI: https://doi.org/10.1007/978-1-0716-4236-8_9

Nat Rev Genet. 2024 Nov 25.

The maternal-to-zygotic transition: reprogramming of the cytoplasm and nucleus.

Mina L Kojima, Caroline Hoppe, Antonio J Giraldez.

A fertilized egg is initially transcriptionally silent and relies on maternally provided factors to initiate development. For embryonic development to proceed, the oocyte-inherited cytoplasm and the nuclear chromatin need to be reprogrammed to create a permissive environment for zygotic genome activation (ZGA). During this maternal-to-zygotic transition (MZT), which is conserved in metazoans, transient totipotency is induced and zygotic transcription is initiated to form the blueprint for future development. Recent technological advances have enhanced our understanding of MZT regulation, revealing common themes across species and leading to new fundamental insights about transcription, mRNA decay and translation.

DOI: https://doi.org/10.1038/s41576-024-00792-0

Int J Mol Sci. 2024 Nov 13. pii: 12197. [Epub ahead of print]25(22):

Abnormalities of Oocyte Maturation: Mechanisms and Implications.

Giorgio Maria Baldini, Dario Lot, Antonio Malvasi, Antonio Simone Laganà, Antonella Vimercati, Miriam Dellino, Ettore Cicinelli, Domenico Baldini, Giuseppe Trojano.

The elucidation of oocyte maturation mechanisms is paramount for advancing embryo development within the scope of assisted reproductive technologies (ART). Both cytoplasmic and nuclear maturation represent intricate processes governed by tightly regulated cellular pathways, which are essential for ensuring the oocyte's competence for fertilization and subsequent embryogenesis. A comprehensive grasp of these mechanisms is vital, as the maturation stage of the oocyte significantly influences chromosomal integrity, spindle formation, and its ability to support the initial stages of embryonic development. By leveraging this knowledge, we can enhance in vitro fertilization (IVF) protocols, refining ovarian stimulation regimens and culture conditions to improve oocyte quality. This, in turn, has the potential to boost pregnancy rates and outcomes. Further research in this area will contribute to the development of novel interventions that aim to increase the efficacy of preimplantation embryonic development, offering new opportunities for individuals undergoing fertility treatments.

Keywords: abnormalities oocyte maturation; assisted reproductive technologies (ART); in vitro fertilization (IVF); oocyte maturation

DOI: https://doi.org/10.3390/ijms252212197