MCB 150 Lecture 21: 21
10 Mar 2017
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Document Summary
The nuclear lamina is a ropelike fibers that give shape and stability to the nucleus. Lamin a and lamin c are alternatively spliced from. In lamina a, but not c, a lipid entity called a farnesyl group gets attached to the protein. Lamina a is initially attached to the nuclear envelope. The farnesyl group is then removed, and the resulting protein is free to be an unbound component of the lamina. Sam"s mom lead the way for the research in progeria. She made the most progress in the disease. A single point mutation in a 57,000 bp-long gene leads to an inability to become de-farnesylated. The resulting mis-processed protein is called progerin. Buildup of the protein causes the disease. Chromatin organization is critical for cell division. Progerin stays attached to the envelope, weakening the lamina and the entire nuclear envelope. Weakening of the lamina limits the cell"s ability to divide. Progerin is found in normal cells in low amounts.
