We have isolated clones which complement the temperature sensitivity and abnormal rRNA processing pattern of the rrp2-2 mutant of Saccharomyces cerevisiae we previously described. DNA sequencing and restriction analysis demonstrated that all clones contain the NMEI gene encoding the RNA of the ribonucleoprotein particle RNase MRP. Deletion analysis showed that the NMEI gene is responsible for the complementation of the rrp2-2 phenotype. A single base change was identified in the nmel gene in the rrp2 mutant, confirming that the RRP2 and NMEI genes are identical. Our experiments therefore indicate that RNase MRP, in addition to its previously reported role in formation of RNA primers for mitochondrial DNA replication [Clayton, D. A. (1991) Trends Biochem. Sci. 16, 107-111], is involved in rRNA processing.

No abstract