High impact information on RRM3

• This slowing was greatly exacerbated in the absence of RRM3, shown here to encode a 5' to 3' DNA helicase [1].
• In addition, mutating the two phenylalanine residues in the PIP-box to alanine or aspartic acid reduces binding to PCNA, confirming that the PIP-box in RRM3 is responsible for interaction with PCNA [2].
• A newly identified temperature-sensitive lethal point mutation in RRM 1 is exacerbated by mutations in the U6 RNA telestem, as is a mutation in RRM 2, but not one in RRM 3 [3].
• This, coupled to our finding that the Rad53p protein kinase is phosphorylated in the rrm3Delta pif1Delta double-mutant strain, leads us to conclude that one mechanism whereby deletion of RRM3 influences mtDNA stability is by modulating mitochondrial deoxynucleoside triphosphate pools [4].
• In addition, we found that over-expression of RNR1, encoding a large subunit of ribonucleotide reductase (RNR), rescued the petite-induction phenotype of a pif1Delta mutation to a similar extent as deletion of RRM3 [4].

Biological context of RRM3

• Instead, deletion of RRM3 alone resulted in an increase in mtDNA point mutagenesis that was synergistic with that caused by a pif1Delta mutation [4].

Other interactions of RRM3

• Here we show that deletion of the RRM3 gene, which encodes a DNA helicase closely related to Pif1p, significantly rescues the petite-induction phenotype of a pif1Delta strain [4].

References