TRANSIENT EXPRESSION OF CLUSTERIN DURING DEVELOPMENT OF PANCREAS

초록

Clusterin has been known to play the important role not only in apoptosis (programmed cell death), but also in compensatory remodeling of damaged tissues and in tissue reorganization during embryonic development. In the present study, thus, we have investigated the developmental expression of clusterin and their tissue distribution in the endocrine pancreas which shows a dynamic rearrangement during embryogenesis as well as against the deleterious stimuli (Park and Bendyan, 1993: Bendyan and Park, 1997).. Although an weak immunoreaction was detected in some pancreatic primordial cells at day 14 of gestation, the distinct custerin expression was identified from the pancreatic tissues at the16th day of gestation by immunocytochemistry as well as by northern blot analysis. We observed clusterin expressed in pancreas to be a disulfide-linked heterodimer of 70kD with a-subunit of 32kD by SDS-PAGE. During the early developmental stage, however, we found that proteolytic internal cleavage in clusterin molecule occurred from the 18th day of gestation. That is, two bands(32kD and 70kD) were observed on the 18th day by western blot analysis even in reducing condition, while only a single 70kD band was seen on the 16 th day and. The steady state level of clusterin mRNA was transiently increased from the 16th day of gestation to 2 days after birth during when an active cellular reorganization took palce to form a normal cellular feature of the islet. On the 18th day of gestation as well as on 2 daysafter birth, the level of clusterin mRNA was highest in the pancreas among tested tissues of the (kidney, brain, liver, heart, lung, and pancreas). In contrast, the lowest expression of clusterin was observed in adult pancreatic tissue, whereas higher clusterin was expressed in normal adult brain and lung.. It suggest that higher expression of clusterin may involve in the action of tissue remodeling or plasticity rather than to be associated with apoptotic cell death.