Mechanisms Preventing Premature Interaction Between Maternal and Paternal Genomes in C. elegans Zygotes

แนวคิดหลัก

Limiting cytoplasmic streaming and maintaining the integrity of the paternal organelle cloud are both important mechanisms that prevent premature interaction between maternal and paternal genomes during C. elegans zygote formation.

บทคัดย่อ

The study investigates the mechanisms that prevent the premature interaction between maternal and paternal genomes during fertilization in C. elegans. Key findings:

The paternal mitochondria and DNA form a discrete cloud that excludes maternal yolk granules and mitochondria, but allows penetration by maternal ER. This exclusion zone is maintained even during cytoplasmic streaming.

The microtubule-severing enzyme katanin and the kinesin-13 motor protein limit the long-range movement of the sperm contents within the zygote, preventing their capture by the meiotic spindle.

The maternal protein ataxin-2 is required to maintain the cohesion of the paternal mitochondria around the sperm DNA. Depletion of ataxin-2 leads to scattering of the paternal mitochondria.

Double depletion of kinesin-13 and ataxin-2 results in increased cytoplasmic streaming and disruption of the paternal organelle cloud, leading to capture of the sperm DNA by the meiotic spindle.

The authors conclude that both limiting cytoplasmic streaming and maintaining the integrity of the paternal organelle cloud are important mechanisms to prevent premature interaction between maternal and paternal genomes during C. elegans zygote formation.

สถิติ

Closest distance between sperm contents and meiotic spindle in control embryos: 18 μm
Closest distance between sperm contents and meiotic spindle in mei-1(RNAi) embryos: 5.5 μm
Closest distance between sperm contents and meiotic spindle in klp-7(RNAi) embryos: 7.7 μm

คำพูด

"Limiting cytoplasmic streaming and maintaining the integrity of the ball of paternal mitochondria are both important for preventing capture events between the meiotic spindle and sperm DNA."
"ATX-2 depletion alters ER morphology, we were not able to score cytoplasmic streaming with the cell-cycle accuracy shown in Fig. 5."

ข้อมูลเชิงลึกที่สำคัญจาก

Katanin, kinesin-13 and ataxin-2 inhibit premature interaction between maternal and paternal genomes in C. elegans zygotes

by Beath,E. A.,... ที่ www.biorxiv.org 03-13-2024

https://www.biorxiv.org/content/10.1101/2024.03.12.584242v1

สอบถามเพิ่มเติม

What other maternal factors might be involved in regulating the cohesion and organization of the paternal organelle cloud

In addition to ATX-2, other maternal factors that could potentially be involved in regulating the cohesion and organization of the paternal organelle cloud include proteins involved in membrane dynamics, cytoskeletal organization, and organelle transport. For example, proteins that regulate endoplasmic reticulum (ER) morphology and dynamics, such as reticulons and other ER-shaping proteins, could play a role in maintaining the structure of the ER envelope around the sperm DNA. Additionally, factors involved in cytoplasmic streaming and microtubule dynamics, like kinesins and microtubule-associated proteins, may contribute to the movement and positioning of the paternal organelles within the zygote. Furthermore, proteins involved in autophagy and organelle degradation pathways could influence the turnover and maintenance of paternal mitochondria and other organelles in the zygote.

How do the mechanisms identified in C. elegans compare to those in other animal species with different fertilization strategies

The mechanisms identified in C. elegans for preventing premature interaction between maternal and paternal genomes during fertilization share similarities with those in other animal species but also exhibit unique features. For example, the exclusion of maternal yolk granules and mitochondria from the volume of paternal cytoplasm introduced to the egg is a common strategy across species to prevent interference with paternal DNA. However, the specific proteins and pathways involved in maintaining the integrity of the paternal organelle cloud, such as katanin, kinesin-13, and ataxin-2, may vary between species. In some species, like mice, a Ran-GTP gradient emanating from the meiotic spindle plays a role in excluding fusion proteins from the oocyte plasma membrane over the spindle, similar to the role of the ER envelope in C. elegans. The insights from C. elegans provide valuable comparative data on the molecular mechanisms underlying fertilization and genome interactions in different animal species.

Could the insights from this study on preventing premature genome interactions be applied to improve assisted reproductive technologies in humans and other mammals

The insights gained from the study on preventing premature genome interactions in C. elegans zygotes could have implications for improving assisted reproductive technologies (ART) in humans and other mammals. By understanding the mechanisms that regulate the movement and organization of paternal DNA and organelles within the zygote, researchers and clinicians could potentially develop strategies to enhance the success rates of ART procedures, such as in vitro fertilization (IVF). For example, optimizing the conditions for sperm-egg interactions to prevent premature fusion over the meiotic spindle could improve the efficiency of fertilization in ART. Additionally, targeting specific factors involved in maintaining the cohesion of paternal organelles could help prevent chromosomal abnormalities and enhance the overall quality of embryos generated through ART techniques. Further research into the molecular pathways identified in C. elegans could lead to novel therapeutic approaches to enhance reproductive outcomes in humans.