CYCLIN A IS REQUIRED IN S PHASE IN NORMAL EPITHELIAL CELL
Abstract
We have investigated cyclin A expression in a primary
culture of normal rat hepatocytes and during rat liver
regeneration after partial hepatectomy. In both cases, cyclin A
mRNA and protein accumulate as the cells enter S phase. To
investigate the potential implication of cyclin A accumulation at
S phase, we microinjected anti-sense DNA constructs for cyclin A,
resulting in effective inhibition of S phase entry. These effects
were specific for cyclin A since anti-sense cyclin B construct had
no similar effects. These results therefore, obtained in normal
epithelial cells, indicate that cyclin A is involved in S phase
and thus should not be only considered as a mitotic cyclin.