Elaborate biochemical reactions regulate passage from one stage to the next.
Genes that determine further cell cycle progression at G1/S including E2F2, CYCLIN E2 (CDC25A, CDC25andnd CDK2, and genes that regulate passage of cells through G2/M (CYCLIN A2 [CDC25C, CYCLIN, CYCLIN B2 [CDC20], CDC20 and CDC2 [CDK1], were down-regulated.
S. pombe and S. cerevisiae have both contributed greatly to our understanding of events and processes that determine and regulate passage through the eukaryotic cell cycle.
By validating similar effects in situ using an immunogold-EM labeling assay in Xenopus oocytes nuclei, they hypothesized that the selective gating mechanism consists of a rapid, stochastic flux of collapsing and distending FG-domains that regulates passage through the NPC (Fig. 4f).
Activation of CDK4 appears to govern exit from the G0 phase and entry into an early G1 phase, and activation of CDK2 regulates transition into and passage through the S phase [ 23].
We found that Postn, Mpeg1, and Racgap1 were biallelically expressed (data not shown), suggesting that the genes corresponding to these ESTs may be regulated by passage number or by an imprinted gene product.
In contrast, there are only two characterized ways by which phosphorylation has been shown to down-regulate passage of cargos through the NPC.
At the molecular level we found that both p19ARF and p16 were progressively up regulated during passages (with respect to the spontaneous level of MEF p0) (Fig. 1B).
Its job is to regulate the passage of chloride ions (electrically charged chlorine atoms) across that membrane.
The two progeny cells may be connected by thousands of plasmodesmata, which contain rings of membrane at each end that are thought to regulate the passage of molecules.
