화학공학소재연구정보센터
Biotechnology and Bioengineering, Vol.100, No.2, 334-343, 2008
Transcriptional regulation of changes in growth, cell cycle, and gene expression of Saccharomyces cerevisiae due to changes in buoyancy
To understand the cellular effects of magnetic traps requires independent analysis of the effects of magnetic field, gravity, and buoyancy. In the current study, buoyancy is manipulated by addition of Ficoll, a viscous substance that can create gradients of buoyancy without significantly affecting osmolality. Specifically, we investigated whether Ficoll induces concentration dependent changes in cell growth, cell cycle, and gene expression in Saccharomyces cerevisiae, with special attention paid to the neutrally buoyant concentration of 35% Ficoll. Cell growth and cell cycle analysis were examined in three strains: wild-type (WT) yeast and strains with deletions in transcription factors Msn4 (Msn4 Delta) or Sfp1 (Sfp1 Delta). Changes in growth were observed in all three strains with WT and Msn4 Delta strains showing strong concentration dependence. In addition, these changes in growth were supported by changes in the cell cycle of all three strains. Gene expression changes were observed in seven GFP-reporter strains including: SSA4, YIL052C, YST2, Msn4 Delta SSA4, SfP1 Delta SSA4, Msn4 Delta YIL052C, and Sfp1 Delta YIL052C. Buoyancy forces had selective concentration dependent effects on gene expression of SSA4 and YIL052C with transcription factor dependence on Msn4. Additionally, SSA4 expression was dependent on Sfp1. YST2 gene expression was not dependent on changes in buoyancy force. This study shows that buoyancy has selective and concentration dependent effects on growth, cell cycle and gene expression, some of which are Msn4 and Sfp1 dependent. For the first time, SSA4 gene expression is shown to be dependent on Sfp1 and YIL052C gene expression is dependent on Msn4.