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#nuclear migration

2 public questions tagged with this topic.

C-Elegans Development-l

Which of the following is required for nuclear migration during C. elegans fertilization?

During fertilization, maternal and paternal pronuclei must migrate centrally and meet before first mitosis for syngamy and diploidy. Sperm aster nucleated by centriole centrosome extends astral microtubules interacting with cortex. Dynein heavy chain DHC-1 with dynactin DNC-1, adaptor LIS-1, and nuclear envelope bridge SUN-1/ZYG-12 KASH drives minus-end directed pulling forces anchored at cortex. Cytoplasmic dynein reels pronuclei inward while pushing female pronucleus posteriorly. Kinesin KLP-18 opposes but dynein dominates net movement. Dynein inhibition via RNAi causes pronuclei to remain peripheral and asymmetric division failure.

Ref: Gonczy et al., Journal Cell Biology: Dynein-driven pronuclear migration and centrosome positioning in C. elegans zygote.

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Elegans -ll

Which protein ensures proper nuclear migration during fertilization?

Upon C. elegans fertilization, oocyte and sperm pronuclei must migrate to meet. After sperm entry at posterior, sperm aster nucleates microtubules. Female pronucleus migration toward centrosome depends on minus-end directed motor dynein anchored on nuclear envelope via SUN-1, ZYG-12 LINC complex. Dynein pulls microtubules, drawing pronuclei together for fusion before first mitosis. Kinesin drives opposite plus-end movement, myosin actin provides cortical but not directed migration. Mutation in dhc-1 heavy chain or dnc mutants blocks pronuclear meeting, resulting in failed karyogamy and embryonic arrest, demonstrating dynein essential for pronuclear migration during fertilization.

Ref: Gonczy et al. 1999; WormBook: Dynein ensures proper nuclear migration during C. elegans fertilization.

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