Purified lectin from skeletal muscle inhibits myotube formation in vitro.

Abstract

A lactose-extractable lectin obtained from 14-16 day embryonic chick pectoral muscle and myotube muscle cultures by affinity chromatography inhibited myotube formation in culture. When applied to muscle cultures at 0.09 .mu.g/ml, the purified lectin produced variable effects on the inhibition of myotube formation related to the time and length of application, suggesting that components of the culture medium and/or temperature produced inactivation. hemagglutination assays showed that the lectin was inactivated by horse serum and by chick embryo extract but not by L-15 salt solution at 4.degree. C. Incubation in L-15 solution at 37.degree. C with or without 2 mM dithiothreitol resulted in inactivation in 2-3 h. To maximize the effect of the lectin on the inhibition of myotube formation, primary muscle cultures were grown in low [Ca2+] medium to inhibit fusion, and then [Ca2+] was increased to elicit fusion in the absence and presence of lectin with solution renewal every 2 h. Without lectin, myotube formation was normal, whereas with lectin it was inhibited by 93%. Continued incubation at 37.degree. C without renewal of lectin resulted in myotube formation, suggesting reversibility by lectin inactivation.