Two NYN domain containing putative nucleases are involved in transcript maturation in XXXX mitochondria.

@entity958 @entity72615 @entity72614
UNASSIGNED: Plant mitochondrial transcripts frequently undergo maturation processes at their 5' ends. This almost completely enigmatic process requires the function of several proteins such as RNA processing factors, which are selectively involved in distinct 5' processing events. Since RNA processing factors represent pentatricopeptide repeat proteins without apparent enzymatic function it is hypothesized that a ribonuclease, most likely with endonucleolytic activity is involved in the 5' end maturation. We have now applied a reverse genetic approach to analyze the role of two potential mitochondrial nucleases, MNU1 and MNU2, in @entity958 . Both proteins contain several RNA binding domains and NYN domains found in other endonucleases. A thorough analysis of various mitochondrial transcripts in MNU1 and MNU2 mutants revealed aberrant transcript pattern characterized by a decrease of mature RNA species often accompanied by an accumulation of larger, 5' extended precursor molecules. In addition, severely reduced amounts of @entity72614 mRNAs in the rpf2-1/mnu2-1 double mutant indicate a corporate function of @entity72615 and MNU2 in the maturation of these transcripts. However, the dramatic reduction of the @entity72614 mRNA is not reflected by the level of the corresponding @entity72614 protein, which is found to be only moderately lowered. Collectively, our analysis strongly suggests a function of MNU1 and MNU2 in 5' processing of plant mitochondrial transcripts. This article is protected by copyright. All rights reserved.
