Roscovitine, a novel cyclin‐dependent kinase inhibitor, characterizes restriction point and G2/M transition in tobacco BY‐2 cell suspension

Abstract

SummaryAlthough the developmental programs of plants and animals differ, key regulatory components of their cell cycle have been conserved. Particular attention has been paid to the role of the complexes between highly conserved cyclin and cyclin-dependent kinases in regulating progression through the cell cycle. The recent demonstration that roscovitine is a potent and selective inhibitor of the animal cyclin-dependent kinases cdc2 (CDK1), CDK2 and CDK5 prompted an investigation into its effects on progression through the plant cell cycle. Roscovitine induced arrests both in late G1 and late G2 phase in BY-2 tobacco cell suspensions. Both blocks were fully reversible when roscovitine was used at concentrations similar to those used in the animal system. Stationary-phase cells subcultured in the presence of roscovitine were arrested at a 2C DNA content. This arrest was more efficient without exogenous addition of plant growth regulator. Roscovitine induced a block in G1 earlier than that induced by aphidicolin. S-phase synchronized cells treated with roscovitine were arrested at a 4C DNA content at the G2/ M transition. The expression analysis of a mitotic cyclin (NTCYCl) indicated that the roscovitine-induced G2 block probably occurs in late G2. Finally, cells in metaphase were insensitive to roscovitine. The purified CDK/cyclin kinase activities of late G1 and early M arrested cells were inhibited in vitro by roscovitine. The implications of these

PhyscomitrellaCyclin-Dependent Kinase A Links Cell Cycle Reactivation to Other Cellular Changes during Reprogramming of Leaf Cells

“…Consistently, the dominant-negative CDKA reduced the amount of RM09 and RM55 transcripts ( Figures 6D and 6E). As an alternative to the dominant-negative CDKA, we used the chemical roscovitine, which inhibits CDKs (Planchais et al, 1997(Planchais et al, , 2000. Roscovitine inhibited the accumulation of CYCB;1 (Figure 7A), cytokinesis ( Figure 7B), the accumulation of RM09 ( Figure 7C) and RM55 ( Figure 7D) transcripts, and tip growth ( Figure 7E).…”

Tangled localization at the cortical division site of plant cells occurs by several mechanisms

“…BY-2 cells were maintained according to the protocols outlined (Nagata and Kumagai, 1999;Kumagai-Sano et al, 2006) and synchronized as previously described (Planchais et al, 1997;Kumagai-Sano et al, 2006). BY-2 cells were transformed using A. tumefaciens (An, 1985) using the TAN-YFP plasmid described (Walker et al, 2007) to create the line AYS9 and also with the CFP-TUA plasmid (Kirik et al, 2007), a kind gift from Viktor Kirik (Illinois State University, Bloomington-Normal, IL), to create AYS9CT5.…”

Stimulation of the cell cycle and maize transformation by disruption of the plant retinoblastoma pathway

“…BY-2 cells enter a stationary phase 7 days after subculturing, when cell density stabilizes, the mitotic index decreases, and cells arrest in G 1 ͞G 0 (43,44). In 7-and 14-day-old cell cultures transfected with 35S:GFP, the proportion of divided foci were significantly lower (20-25%) than that of 4-day-old cell cultures (t test, P Ͻ 0.01; Table 1).…”