Fig. 1. Nuclear shape abnormalities and uneven distribution of A- and B-type lamins in fibroblasts from FPLD patients. (A) Control and FPLD-fixed cells were labelled with DAPI, rabbit anti-lamins B antibodies (LB, green) and mabs directed against lamins A/C (LA/C, red), before analysis by conventional immunofluorescence microscopy. Two control nuclei are shown, a regular ovoid nucleus and a dysmorphic budding nucleus (arrowhead), the latter being observed in a low percentage of cells (2-3%). In the two nuclei, A- and B-type lamins are detected at the periphery, including in the bud. In the nucleus from an FPLD patient, A- and B-type lamins colocalize at the periphery of the main part of the nucleus, whereas A-type lamins predominate in the buds. Note that one bud contains a continuous A-type lamin meshwork (arrowhead), whereas the lattice in the other one is discontinuous (asterisk). Note also the faint DAPI staining of DNA, especially in the buds. (B) Cells from a control individual and from FPLD patients JM (LaA/C R482Q) and LM (LaA/C R482W) were treated as described above and examined by confocal microscopy. As in A, B-type lamin staining was weak or absent in buds, whereas signals for A-type lamins were of a normal intensity. Note the variation in size and shape of the nuclear herniations, some being connected to the nucleus by large necks (arrowheads), others showing a strong lamin staining at their base (arrows). Note also the honeycomb aspect of both lamin types meshworks in some buds or poles (asterisks). Bars, 10 µm.