Table I.

Percentage of Bcl-2–positive C2C12 Cells That Coexpressed Additional Muscle-specific Proteins 

Protein examined		Culture condition*		Number of Bcl-2+ cells examined‡		Percentage (number) ofBcl-2+ cells that coexpressed the examined protein
Desmin		GM		314		85.6% (269)
		1 d DM		300		69.7% (209)
		3 d DM		302		13.9% (42)
		4 d DM		300		14.7% (44)
Myf-5		GM		303		21.5% (65)
		1 d DM		298		5.4% (16)
		2 d DM		317		5.7% (18)
		4 d DM		320		0.0% (0)
MyoD		GM		380		18.9% (72)
		1 d DM		300		3.0% (9)
		2 d DM		290		4.8% (14)
		4 d DM		305		0.0% (0)
Myogenin		All		≥300		0.0% (0)
MRF4		All		≥300		0.0% (0)
Myosin		All		≥300		0.0% (0)

^* As indicated, cells were stained either when they were near confluence in growth medium (GM) or during myotube formation after 1 d, 2–3 d, or 4 d in differentiation medium (DM).  

^‡ Cultures were double immunostained and scanned for Bcl-2–positive cells. Each Bcl-2–positive cell was examined for coexpression of the tested protein. As described in the text, Bcl-2–positive cells amounted to ∼10% of the total number of mononucleate cells at all culture stages.