Fig. 6.

Maintenance of myomesin expression is required for M-band integrity. Confocal micrographs of primary cultures of neonatal rat cardiomyocytes (NRC) either transiently transfected with control plasmid (top row) or myomesin knockdown (KD) plasmid ([55]; four bottom rows) for eight days. The plasmids also encode for GFP to be able to identify the transfected cells (second column). Depletion of myomesin by knockdown in actively contracting NRC leads to disrupted myofibrils (second, fourth row), unless the cardiomyocytes already have started to express M-protein (third row) or contraction is prevented by the addition of verapamil (V) to the culture medium. Antibodies used for immunostaining and their colours in the overlay are indicated in the individual panels. Scale bar = 10 μm.