Mechanisms of nuclear pore complex disassembly by the mitotic Polo-like kinase 1 (PLK-1) in embryos.

The nuclear envelope, which protects and organizes the genome, is dismantled during mitosis. In the zygote, nuclear envelope breakdown (NEBD) of the parental pronuclei is spatially and temporally regulated during mitosis to promote the unification of the maternal and paternal genomes. Nuclear pore complex (NPC) disassembly is a decisive step of NEBD, essential for nuclear permeabilization.

Mechanisms of Nuclear Pore Complex disassembly by the mitotic Polo-Like Kinase 1 (PLK-1) in embryos.

Unlabelled: The nuclear envelope, which protects and organizes the interphase genome, is dismantled during mitosis. In the zygote, nuclear envelope breakdown (NEBD) of the parental pronuclei is spatially and temporally regulated during mitosis to promote the unification of the parental genomes. During NEBD, Nuclear Pore Complex (NPC) disassembly is critical for rupturing the nuclear permeability barrier and removing the NPCs from the membranes near the centrosomes and between the juxtaposed pronuclei.

PLK-1 promotes the merger of the parental genome into a single nucleus by triggering lamina disassembly.

Life of sexually reproducing organisms starts with the fusion of the haploid egg and sperm gametes to form the genome of a new diploid organism. Using the newly fertilized zygote, we show that the mitotic Polo-like kinase PLK-1 phosphorylates the lamin LMN-1 to promote timely lamina disassembly and subsequent merging of the parental genomes into a single nucleus after mitosis. Expression of non-phosphorylatable versions of LMN-1, which affect lamina depolymerization during mitosis, is sufficient to prevent the mixing of the parental chromosomes into a single nucleus in daughter cells.

Combining near-infrared fluorescence with Brainbow to visualize expression of specific genes within a multicolor context.

Fluorescent proteins are a powerful experimental tool, allowing the visualization of gene expression and cellular behaviors in a variety of systems. Multicolor combinations of fluorescent proteins, such as Brainbow, have expanded the range of possible research questions and are useful for distinguishing and tracking cells. The addition of a separately driven color, however, would allow researchers to report expression of a manipulated gene within the multicolor context to investigate mechanistic effects.