Cytokinesis is more rapid in Ha‐T24‐ras transfected rat embryo fibroblasts than in non‐transfected control cells

Abstract

It has long been known that neoplastic cells are characterized by increases in cell motility. Earlier studies from this laboratory indicated that mitotic events were also altered in many tumor and experimentally transformed cells and that this included increases in metaphase duration and a reduction in the duration of cytokinesis. The studies presented in this paper were done to determine whether or not transfection of normal rat embryo fibroblasts by the Ha-T24-ras oncogene could also produce such alterations in mitotic events. The results obtained with the use of time lapse video microscopy indicate that neither the duration of metaphase nor the rate of chromosome movement during anaphase was altered but that the rate of furrow progression during cytokinesis occurred at a significantly more rapid rate. Thus, the cellular alterations induced by transfection with Ha-T24-ras accelerate microfilament-dependent cytokinetic furrowing without significant effects on microtubule-dependent mitotic events. One of several possible mechanisms that could account for these observations involves a down regulation of protein kinase C which has been reported to occur in many neoplastic cells including those transformed by ras. Such a hypothesis could also have broader implications because it may be applicable to the increase in motility and metastatic activity generally observed in transformed cells.

Dictyostelium RasG Is Required for Normal Motility and Cytokinesis, But Not Growth

“…Schizosaccharomyces byr4 , a suppressor of ras1 mutations ( Song et al, 1996 ), appears to encode a regulated inhibitor of cytokinesis. Furthermore, activating Ras mutants increase the rate of cytokinesis in mammalian cells ( Ng et al, 1992 ). There is also an increasing amount of evidence that the small GTPases Rac, Rho, and Cdc42 are centrally involved in cytokinesis ( Dutartre et al, 1996 ), and Ras appears to act as an upstream regulator of their activities.…”

Cytological effects of the microinjection of antibody to ras p21 in early cleavage Xenopus embryos

“…Incorporation into the cell surface may occur via an exocytic step requiring the involvement of intracellular vesicles and the plasma membrane. ras-like proteins could be involved in such a membrane translocation process, either by controlling microtubule organization (Schmitt et al, 1986) or microfilament function (Therrien and Naccache, 1989;Ng et al, 1989) or by affecting membrane traffic (Goud et al, 1988).…”