Distribution of MyHC-like antigens is retained in epidermal cells in tissue culture and mimicked in cardiomyocytes. Primary dissociates of P1 rat skin (A-D) were grown in culture and stained for A4.840 (A) or N3.36 (C) and A4.74 (B,D) by dual immunofluorescence. After two days in culture, fibrillar A4.74-reactive material is visible in large spindle-shaped cells, some of which did not contain A4.840-reactive material (arrows, A,B). Other A4.74-reactive cells do contain A4.840-antigen (insets A,B). Large 'donut' cells contain abundant A4.840-reactive dots near the cell surface (arrowhead, A). These donut cells are probably from the prickle cell layer of the surface epidermis based on a) the appearance of cells of similar morphology in the prickle cell layer of cryosections of near-dissociated trypsinised skin and b) the presence of these cells in dissociated 'epidermal' layer cultures, but not in 'dermal' layer cultures that contain numerous dermis and hair follicle cells but little surface epidermis (data not shown). After one day in culture, N3.36-labelled material is also fibrillar (arrow, C) but is co-expressed in A4.74-reactive cells extremely rarely (C,D). Confocal microscopy of primary cultures of neonatal rat cardiomyocytes (E-O) revealed staining for A4.840 (E,H,K,L,O), plakoglobin (F), pan-cadherin (J,N), desmoplakin (G), myomesin (I,K) and desmin (M,O) by triple immunofluorescence. Significantly enhanced A4.840-antigen is detected at the junctions between cells that are marked by plakoglobin and desmoplakin (E-G). Cytoplasmic A4.840-reactivity is also present in some cells, and co-localises in M-lines detected by myomesin (H-J, shown in higher magnification in K,O). Other cells containing sarcomeric striations do not contain detectable A4.840-antigen (asterisks, H-J). The A4.840-antigen is not localised in the Z line marked by desmin (L-O). Bars = 2 μm in K,O, 10 μm in rest.
Jazwinska et al. BMC Cell Biology 2003 4:10 doi:10.1186/1471-2121-4-10