EFFECTS OF INHIBITING TRANSGLUTAMINASE DURING EGG FERTILIZATION AND DEVELOPMENT

Transglutaminase inhibitor 3,4,5-tetramethyl-2-[(2-oxopropyl)thio]imid azolium chloride or L-682777) affected the appearance of the fertiliza tion envelope (FE) and subsequent development in Sphaerechinus granula ris and Arbacia punctulata in a concentration-dependent manner. Abnorm alities were first visible in forming FE's at the lowest concentration (0.001 mM) of the inhibitor used. The wrinkled appearance of FE's sug gested that the treatment prevented the I-T transition, whereas the fi nding of numerous denuded cells and empty FE's indicated that the inhi bitor acted by rendering the FE's very fragile. Cell division by the 2 -cell stage was also affected by this active-site-directed transglutam inase inhibitor. With 0.05 mM of the inhibitor, about 50% of all cells were polynucleated. In view of earlier findings that other transgluta minase inhibitors can produce abnormalities with regard to FE wrinklin g and deranged cell division, it can be suggested that different forms of transglutaminases might be involved at various stages in embryonic development. (C) 1994 Academic Press. Inc.