10Sa RNA: processing by and inhibition of RNase III.

Characterization of the maturation of precursor 10Sa RNA revealed that RNase III processed p10Sa RNA to two intermediate molecules. We showed that the intermediates are not conformers and both are larger than the mature 10Sa RNA. Cell extracts further process the RNase III products to an RNA molecule which has a different conformation than 10Sa RNA but is approximately the same size as 10Sa RNA. An inhibitor of p10Sa RNA processing by RNase III was identified. It is a protein, with a molecular mass of approximately 17 kDa.