Figure 5

Transgene expression is restricted to fast skeletal muscle fibres and is expressed in a similar fibre type as the endogenous locus. A) A section from an interior leg muscle of a transgenic chicken was stained for β-galactosidase activity. The animal was at least four months old when assayed. B) A serial section to the one above was immuno-stained for fast (red) and slow (green) muscle isoforms. Fibres that are negative for β-galactosidase are labelled with an antibody to slow muscle. C) A section from an interior leg muscle of a second line of transgenic chicken was stained for β-galactosidase activity. D) A serial section to the one above was immuno-stained for MLC1 and 3 muscle isoforms (green). Fibres that are negative for β-galactosidase do not express MLC1 and 3. White arrows indicate corresponding myofibres. Scale bars, 0.1 mm.