Cell Growth Control
I. RNA decay and bacterial cell growth
One of our research interests relates to the mechanism of RNA decay and its important role in gene regulation in prokaryotic cells. Using genetics, molecular and biochemical approaches, and DNA chips, we demonstrated the important roles of RNA decay in the control of DNA replication of ColE1-type plasmids and for normal cell growth; isolated and characterized the RNA degradosome(a multicomponent ribonucleolytic complex that contains RNaseE, PNPase, enolase and RhlB RNA helicase; and proved the existence of RNA degradosome complex in vivo and tethering to the cytoplasmic membrane. Our current investigations are aimed at understanding the molecular basis by which the RNA degradosome acts to control normal cell growth.
II. Mammalian growth arrest genes
The mechanism controlling the maintenance of and departure from the cellular growth-arrested state, which could be regulated by the genes predominantly expressed during the growth-arrest or growth arrest-specific genes (gas), is not clear. To understand the functions of mammalian gas genes, we identified and characterized four gas genes (gas7-gas10) by using retrovirus-based ¡§gene-trapping¡¨ vectors in the mouse NIH3T3 fibroblast. Using molecular and cell biology, biochemistry, and the mouse model system, we discovered that these gas genes mediate a variety of biological functions including cell survival, proliferation and growth suppression, cell differentiation and apoptosis. Currently, we focus on the molecular basis and functions of two gas genes-gas7 and gas8-during various cell processes that include neuronal differentiation.