Sidney Altman Sterling Professor of Molecular, Cellular & Developmental Biology » Molecular Cell Biology, Genetics and Development » Microbiology » B.S. M.I.T. 1960; Ph.D. University of Colorado, Boulder 1967 We study the properties of an essential enzyme, RNase P. In E. coli, this enzyme has a catalytic RNA subunit, and one protein subunit. In eucaryotes, however, specifically yeast and human cells, the subunit structure of the enzyme is much more complex. We are in the process of characterizing the human and yeast enzymes both with respect to composition and to function of the individual subunits. We are also engaged in developing a method of controlling gene expression in vivousing RNase P. To date, we have shown that this new methodology can effectively inhibit the expression of genes responsible for drug resistance in E. coliand can prevent infection of mammalian cells in tissue culture by influenza virus. Jarrous, N., Wolenski, J.S., Wesolowski, D., Lee, C., and Altman, S. (1999). Localization in the nucleolus and coiled bodies of protein subunits of the ribonucleoprotein ribonuclease P. J. Cell Biol. 146-3:559-571. Pomeranz, D.A. and Altman, S. (1999). Verification of phylogenetic predictions in vivo and the importance of the tetraloop motif in a catalytic RNA. Proc. Natl. Acad. Sci. (USA) 96:11200-11205.