EXPRESSION OF TRANSGLUTAMINASE-C DURING THE PRENATAL DEVELOPMENT OF HUMAN SUBMANDIBULAR GLANDS

The involvement of transglutaminase C (TGase C) in morphogenesis and c ytodifferentiation during glandular tubule formation was addressed by immunolocalization of the protein at different stages of prenatal huma n submandibular gland development in 100 fetuses and 20 adult salivary glands. Immunocytochemical detection was carried out using a monospec ific antibody to TGase C. The results showed TGase C reactivity in bot h acini and ducts early in development (from 10 to 14 weeks), followed by a marked increase in ductal activity and a decline in acinar activ ity up to 32 weeks. During the peak of reactivity at 25 to 32 weeks, s taining was concentrated in the apical ends of the columnar cells. In the adult, staining was weakly and diffusely distributed in the striat ed and excretory ducts. Western blot analysis of the cellular extracts of pooled samples from various stages of salivary gland development s howed a single strong band at 76 kDa early in development. This band b ecame weaker after 32 weeks of prenatal development and in the adult. These findings of transient high expression of TGase C, which coincide with the development of tubulo-alveolar structure, suggest that TGase C may play a role in morphogenesis in human salivary gland developmen t.