Hebrew U.-Johns Hopkins study of nuclear envelope defects provides clues to dealing with human disease

A step towards understanding cell mutations that cause a variety of human diseases, particularly in children -including that which brings about premature aging and early death – has been taken by researchers at the Hebrew University of Jerusalem Silberman Institute of Life Sciences and the John Hopkins University School of Medicine.

The scientists have focused their research on a study of induced mutations in the nuclear envelope of cells from the tiny C. elegans worm. Their aim is to thus provide clues towards a better understanding of mutations in proteins of the envelope of the cell nucleus in humans.

Such mutations, particularly in lamin (nuclear envelope) proteins A and C, cause many different diseases, including Hutchison Gilford progeria syndrome. Children with this disease develop premature aging and die usually before the age of 13. Other diseases brought about by these mutations include a form of muscular dystrophy, cardiomyopathy (a weakening of the heart muscle), and various other forms of irregular or retarded growth in childhood.

A report on the lamin research project was published in a recent issue of the Proceedings of the National Academy of Sciences in the U.S. The project was carried out primarily by Ayelet Margalit, a doctoral student in genetics at the Hebrew University, working under the supervision of Prof. Yosef Gruenbaum, and in cooperation with Prof. Katherine L. Wilson and Dr. Miriam Segura-Totten of Johns Hopkins University.

Experimenting with removal of the worm’s lamin protein or its interacting protein partners emerin, MAN1 or BAF, the researchers have described “down-the-line” consequences, including the disruption of various proteins necessary for normal cell reproduction. Even though the C. elegans worm has only one lamin protein and few proteins that interact with it, the processes that occur there are similar to what happens in humans and provide clues to the laminopathic diseases affecting people..

The results seen from these lamin complex disruptions are a halted process of cell division, resulting in a static “bridge” structure between cells that should have separated, plus damage to the gonad cell structure. In both cases, the ability of the organism to grow and to reproduce is severely impaired.

The researchers hope that through further laboratory experimentation with the worm they will be able to better understand the functions of lamin-based complexes, and why mutations in these proteins cause a variety of different laminopathic diseases, such as progeria and muscular dystrophy in humans.