Primary muscle cells cultivated in medium conditioned by spinal cord cells show changes in messenger RNA as detected by translation in ovo accompanied by synthesis of extracellular matrix components.

ABSTRACT

Primary muscle cell cultures were prepared from rat embryos and maintained in normal (unconditioned) and spinal cord (conditioned) media. In order to relate translational regulation to the morphological changes associated with each culture condition, mRNA was isolated from both culture variants and subjected to in ovo translation. Xenopus oocytes were injected with mRNA and their incubation media checked for the presence of newly formed proteins coded by the mRNAs and secreted into the medium. Electrophoretograms indicated mRNA-dependent synthesis of several proteins in the molecular mass range of 30-260 kD. To further characterize these proteins, antisera directed against several extracellular matrix proteins were used for immunoprecipitation antigens recognized by anti-heparan-sulfate-proteoglycan and anti-fibronectin were enhanced in conditioned cells, whereas laminin was found to be reduced.