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. 1995 Sep;15(9):4763–4770. doi: 10.1128/mcb.15.9.4763

RPM2, independently of its mitochondrial RNase P function, suppresses an ISP42 mutant defective in mitochondrial import and is essential for normal growth.

C K Kassenbrock 1, G J Gao 1, K R Groom 1, P Sulo 1, M G Douglas 1, N C Martin 1
PMCID: PMC230720  PMID: 7544434

Abstract

RPM2 is identified here as a high-copy suppressor of isp42-3, a temperature-sensitive mutant allele of the mitochondrial protein import channel component, Isp42p. RPM2 already has an established role as a protein component of yeast mitochondrial RNase P, a ribonucleoprotein enzyme required for the 5' processing of mitochondrial precursor tRNAs. A relationship between mitochondrial tRNA processing and protein import is not readily apparent, and, indeed, the two functions can be separated. Truncation mutants lacking detectable RNase P activity still suppress the isp42-3 growth defect. Moreover, RPM2 is required for normal fermentative yeast growth, even though mitochondrial RNase P activity is not. The portion of RPM2 required for normal growth and suppression of isp42-3 is the same. We conclude that RPM2 is a multifunctional gene. We find Rpm2p to be a soluble protein of the mitochondrial matrix and discuss models to explain its suppression of isp42-3.

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Selected References

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