RNase P RNA from the Sulfolobales

J. Kirk Harris, and James W. Brown, North Carolina State University, Raleigh, NC 27695 USA

RNase P is responsible for the catalytic removal of the 5' leader sequence from precursor tRNAs. This enzyme is a ribozyme, i.e. it contains both an RNA component and a protein component. In Bacteria the RNA alone is able to perform the correct catalytic event in vitro at elevated salt concentrations. In the Archaea, this is not the case. In all cases examined the RNA alone has not been shown to be catalytic in vitro. This is suprising considering the high degree of similarity between the Bacterial and Archaeal sequences and secondary structures. To further understand this loss of catalysis in the Archaeal RNAs, representative RNAs from various phylogenetically diverse organisms are being cloned and sequenced. These sequences are being used for comparative analysis of the RNAs structure and for the design of PCR primers to facilitate better coverage of environmental DNA samples as sources for RNase P RNA genes. This work has been focused so far on the Crenarchaea, with the Sulfolobales as the primary group characterized. The RNase P RNA gene has been cloned and sequenced from five organisms: Acidianus ambivalens (Desulfurolobus ambivalens), Acidianus breirleyi, Metallosphaera sedula, Sulfolobus shibatae, and Sulfolobus solfataricus.