Fig. 2
From: Developmental myosins: expression patterns and functional significance
Embryonic MyHC in adult skeletal muscles. a Transverse sections of rat extraocular muscle (rectus superior) reacted with a monoclonal antibody specific for MyHC-emb (BF-G6, see [76]). Note that embryonic myosin is expressed in most fibers of the orbital layer (O) but only in rare fibers of the global layer (G) of the muscle. Bar = 100 μm. b Embryonic myosin in intrafusal fibers of muscle spindles. Serial sections of rat soleus muscle viewed in phase contrast or stained for MyHC-emb (MYH3), MyHC-slow-tonic (MYH7b), or MYH15 (MYH15). Embryonic myosin is detected in the nuclear chain fibers of a muscle spindle (3 and 4) but not in the nuclear bag fibers (5 and 6), nor in the extracapsular region of an adjacent spindle (fibers 1 and 2). Extrafusal muscle fibers (asterisk) are unstained. Bar = 20 μm (modified from [22])