An investigation of emerin and nuclear lamins: : Interactions, distribution, and role in cell cycle regulation, in cells derived from EDMD patients.

Abstract

Emery Dreifuss muscular dystrophy (EDMD) is caused by mutations either in the gene encoding emerin or in the gene encoding A-type lamins (lamins A and C). Several roles for emerin and A-type lamins have been proposed, including their involvement in nuclear structure, gene expression, cell cycle progression, and DNA replication. However, their functions are poorly understood and thus the mechanisms by which mutations cause different inherited diseases are not clear. In this project, the endogenous and exogenous distribution of emerin, and A- and B-type lamins in lymphoblasts and fibroblasts carrying mutations in emerin and A-type lamins have been investigated. For this purpose, anybodies against emerin, and A- and B-type lamins as well as GFP-, and DsRed- tagged fusion proteins (GFP-emerin, GFP-lamin A, and DsRed-lamin C) were used. From the immunofluorescence microscopy results of lymphoblasts, it is suggested that the distribution of emerin and lamins is possibly affected in these cells in EDMD. However, in fibroblasts there was no evidence of structural abnormality for the proteins investigated. The effects of emerin and A-type lamins mutations on growth and progression of cells through the cell cycle have also been investigated in fibroblasts of EDMD patients, using flow cytometry. The results obtained here suggest that emerin and lamin mutations may cause a cell cycle arrest at the G0 phase of the cycle.