Exposure of zebrafish nuclei to meiotic cytosol resulted in phosphorylation of NEP55 and L68 proteins by cyclin- dependent kinase 2. NEP55 is a protein of the inner nuclear membrane, and L68 is a protein of the nuclear lamina. What is the most likely role of phosphorylation of these proteins in the process of mitosis?
A) They assist in the movement of the centrosomes to opposite sides of the nucleus.
B) They enable the attachment of the spindle microtubules to kinetochore regions of the centromere.
C) They are involved in the disassembly and dispersal of the nucleolus.
D) They are involved in the disassembly of the nuclear envelope.

Question

Quizplus · Accepted Answer

The phosphorylation of NEP55 and L68 proteins by cyclin-dependent kinase 2 is most likely involved in the disassembly of the nuclear envelope during mitosis. NEP55 is a protein of the inner nuclear membrane, and L68 is a protein of the nuclear lamina, which provide structural support to the nuclear envelope. Phosphorylation of these proteins may cause their dissociation from the lamina, leading to disassembly of the nuclear envelope and facilitating the movement of chromosomes into the cytoplasm for segregation. Therefore, the most likely role of this phosphorylation is the disassembly of the nuclear envelope, as occurs in mitosis.

Exposure of Zebrafish Nuclei to Meiotic Cytosol Resulted in Phosphorylation