Developmental regulated expression of syndecan-1 and glypican in pectoralis major muscle in turkeys with different growth rates

Heparan sulfate proteoglycans, syndecan-1 and glypican, are low-affinity receptors for fibroblast growth factor 2 (FGF2). Since FGF2 stimulates skeletal muscle cell proliferation but inhibits differentiation, differences in syndecan-1 and glypican expression might affect muscle development and growth by changing the intensity of FGF2 signaling. In the present study, the pectoralis major muscle from 14 to 24-day-old-embryos, and from 1 to 16-week-old birds from a turkey line (F) selected for increased 16-week bodyweight and its genetic control line (RBC2), were used to address how syndecan-1 and glypican are expressed during skeletal muscle formation. The expression of syndecan-1 and glypican was measured by semiquantitative reverse transcription polymerase chain reaction. For males, the F-line embryos expressed more syndecan-1 (days 14 and 16) and glypican (days 14 and 18) than the RBC2 line. Similar line differences for males were observed during posthatch development. The male embryos from both lines expressed more syndecan-1 at days 18 through 22 and more glypican at days 20 and 22 than the corresponding females. The temporal and spatial distribution of syndecan-1 and glypican was detected by in situ hybridization. Syndecan-1 was identified in all muscle fibers at all embryonic stages studied, whereas the glypican was detected from embryonic day 18. The data from the current study provided new information about the expression of syndecan-1 and glypican as it relates to skeletal muscle growth properties.