Question

You are studying nuclear lamins and use recombinant DNA technology to alter the coding sequence of a nuclear lamin gene. The alteration you make creates a situation such that the gene now codes for a nuclear lamin protein that can no longer be phosphorylated when the nuclear envelope is broken down during mitosis. What do you predict would happen if the cell only had the altered nuclear lamin gene (and not the unaltered version)

Answer 1

Nuclear lamins will no longer disassemble during mitosis

Step-by-step explanation:

The nuclear lamina is a fibrillar network inside the nucleus of eukaryotic cells, between the inner nuclear membrane and the peripheral chromatin. Nuclear lamins (also called simply lamin proteins) are intermediate filament-type proteins and represent the major building blocks of the nuclear lamina. During mitosis, the nuclear lamina is disassembled by hyperphosphorylation of nuclear lamins and lamina-associated proteins. The protein responsible for phosphorylating nuclear lamins is p34cdc2, a protein kinase that has a key role in controlling cell cycle progression. In consequence, a mutant form of the nuclear lamin proteins that cannot be phosphorylated will no longer be able to disassemble during mitosis.