Purothionin from wheat endosperm reversibly blocks myogenic differentiation of chick embryonic muscle cells in culture.
Purothionin from wheat endosperm is a cysteine-rich, basic polypeptide of about 5000 Da, which modifies membrane permeability of cultured mammalian cells. This peptide was found to block fusion of chick embryonic muscle cells in culture but allows proliferation and alignment. A purothionin concentration of 6 micrograms/ml (1.2 microM) was necessary for the complete prevention of myotube formation. Under similar conditions, incorporation of [35S]methionine occurred normally but the synthesis of muscle-specific proteins including creatine kinase and acetylcholine receptor was strongly inhibited. In addition, purothionin blocked the uptake of 86Rb+, immediately after its addition to the cultured myoblasts. No such effects were found with the purothionin chemically modified with acetic or succinic anhydride. Thus, the basic residues in purothionin appear to be associated with the inhibition of myogenic differentiation. These results suggest that purothionin exerts its regulatory effect on the transition from proliferative to differentiative myoblasts by interfering with membrane permeability or intercellular contact and recognition, which are necessary for the initiation of muscle differentiation.
Kwak
K B
KB
Department of Zoology, College of Natural Sciences, Seoul National University, Korea.
Lee
Y S
YS
Suh
S W
SW
Chung
C S
CS
Ha
D B
DB
Chung
C H
CH
D000818:Animals; D023181:Antimicrobial Cationic Peptides; D002454:Cell Differentiation / Q000187:drug effects*; D002455:Cell Division / Q000187:drug effects; D002459:Cell Fusion / Q000187:drug effects; D002463:Cell Membrane Permeability / Q000187:drug effects; D002478:Cells, Cultured; D002642:Chick Embryo; D003402:Creatine Kinase / Q000096:biosynthesis; D005433:Flour; D007700:Kinetics; D009132:Muscles / Q000166:cytology* / Q000187:drug effects; D010940:Plant Proteins / Q000302:isolation & purification / Q000494:pharmacology*; D011950:Receptors, Cholinergic / Q000096:biosynthesis / Q000187:drug effects; D013329:Structure-Activity Relationship; D014118:Toxins, Biological / Q000494:pharmacology; D014908:Triticum
D023181:Antimicrobial Cationic Peptides; D010940:Plant Proteins; D011950:Receptors, Cholinergic; D014118:Toxins, Biological; C016085:purothionin; D003402:Creatine Kinase