RNAse III function in bacteria – insights gained from Sinorhizobium meliloti

Goodfellow S1, Zhang D1,2, Wang MB2 and Zhang R1

  1. Wollongong University, Northfields Ave, Wollongong NSW 2522, Australia.
  2. CSIRO Agriculture, Clunies Ross Street, Canberra, ACT 2601, Australia.

The RNAse III superfamily is a diverse group of enzymes involved in the maturation, processing and degradation of double-stranded or secondarily structured RNA species in both Eukaryotes and Prokaryotes. Previous studies in Escherichia coli have shown that while RNAse III plays a central role in ribosomal RNA maturation and post-transcription regulation, deletion is non-fatal - in spite of noticeable aberrations in rRNA subunit maturation. This importance necessitates further research in terms of extending existing knowledge of the detailed molecular function, and also the diversity of these RNAse III enzymes and their roles in other bacterial taxa. This study intends to address this by using a homologous recombination-based strategy to delete RNAse III in the model nitrogen fixation bacterium - Sinorhizobium meliloti. This will be followed by an investigation of the resultant effects on growth and RNA metabolism in comparison with E. coli. An RNAse III deletion strain has been isolated and the mutant - S. meliloti RmL7, is viable showing no noticeable defects in terms of growth. Work is in progress to uncover the global post-transcriptional regulatory effect of the deletion in both S. meliloti and E. coli in addition to further documentation of rRNA biogenesis.