Cell adhesion to substratum and activation of tyrosine kinases are essentially required for G1/S phase transition in BALB/c 3T3 fibroblasts

AbstractCell adhesion to substratum and activation of tyrosine kinases are essential for the progression of cell cycle through G1 phase in mammalian cells. The kinetic studies of mouse BALB/c 3T3 fibroblasts showed that serum was no longer required for the progression of G1/S phase transition. In contrast, cell adhesion was essentially required in late GI phase, especially at the period of G1/S transition. Among the kinase inhibitors used to elucidate the signal transduction caused by cell adhesion, tyrosine kinase inhibitors, genistein and herbimycin A, blocked the G1/S transition most effectively when cells were exposed to the inhibitors at the period of GI/S transition. Cell adhesion was not critically required for cells to undergo DNA synthesis once they had passed the G1/S boundary, and the effects of tyrosine kinase inhibitors on the progression of S phase were also not critical. The expressions of histone H2B and dihydrofolate reductase (DHFR) genes (S phase specific genes) and also the transcription factor E2F-1 gene (an activator of DHFR gene) were suppressed when cells were cultured without adhesion or exposed to the tyrosine kinase inhibitors. These results suggest that cell adhesion to substratum plays an important role in the G1/S phase transition of mouse BALB/c 3T3 fibroblasts through the activation of tyrosine kinases other than growth factor receptor-tyrosine kinases

Chromosome Scaffold is a Double-Stranded Assembly of Scaffold Proteins

Poonperm, R., Takata, H., Hamano, T. et al. Chromosome Scaffold is a Double-Stranded Assembly of Scaffold Proteins. Sci Rep 5, 11916 (2015). https://doi.org/10.1038/srep11916

SuperNova, a monomeric photosensitizing fluorescent protein for chromophore-assisted light inactivation

Takemoto, K., Matsuda, T., Sakai, N. et al. SuperNova, a monomeric photosensitizing fluorescent protein for chromophore-assisted light inactivation. Sci Rep 3, 2629 (2013). https://doi.org/10.1038/srep02629

Studies on the Herbaceous Cutting Propagation in Chrysanthemum morifolium (1) : Influences of Temperatures on the Increasing Rate of Adventitious Root

In the vegetative propagation with aterminal cutting in Chrysanthemum morifolium \u27Ki-Amagahara\u27, the efects of controlled environmental factors of four temperature levels of 30℃, 25℃, 20℃ and 15℃,and a continuous light regime in 25℃, on the rooting responses and the increasing rate in number of roots were investlgated. Callus formation and rooting were recognized as faster in higher temperatures than in lower ones in the order of 30℃, 25℃, 20℃ and 15℃, and, under the continuous light regime, the rooting was promoted as compared with the cutting in natural photoperiod. On the other hand,in the increasing rate in number of roots there was no significant differences among the cuttings in those temperatures. A certain regression coefficient of +3.662 was reckoned as an average. It was suggested that the increasing rate of adventitious root in Chrysanthemum cuttings were not affected under any temperature conditions and continuous light regime.栽培ギクのさし芽繁殖に際してのカルスの形成,不定根形成の早さ,および根数の増加の程度に及ぼす環境要因の影響を温度ならびに日長に関しての制御環境条件のもとで品種\u22黄天ケ原\u22を使用して調査した.温度条件は30℃,25℃,20℃ および15℃の4段階に設定し,別に25oC 全日長区を設けた.各温度区におけるカルスの形成および不定根形成の早さは30℃区が最も早く,ついで25℃全日長,25℃,20℃,15℃区の順であった. また発根数の増加の割合は,各温度区とも大差がなく,直線回帰係数の平均値は+3.662となり,仝日長区で示された同値+3.699とともに板数増加には品種あるいは時期的な差は別として温度,および日長条件によって影響をうけ難いことが示唆された