Disease relevance of CCE1

• These data indicate that the activity has a strong DNA structure selectivity as well as a limited sequence preference; features similar to the Holliday junction resolving enzymes RuvC of Escherichia coli and the mitochondrial CCE1 (cruciform-cuttingenzyme 1) of Saccharomyces cerevisiae [1].
• Holliday junction resolvases with distinct properties have been characterized from bacteriophages (T4 endo VII, T7 endo I, RusA and Rap), Bacteria (RuvC), Archaea (Hjc and Hje), yeast (CCE1) and poxviruses (A22R) [2].

High impact information on CCE1

• Only two cellular junction-resolving enzymes have been identified to date: RuvC in eubacteria and CCE1 from Saccharomyces cerevisiae mitochondria [3].
• Recent studies have brought about a reappraisal of the origins of junction-specific endonucleases with the discovery that RuvC, CCE1 and A22R share a common catalytic core [2].
• In Saccharomyces cerevisiae, the enzyme CCE1 is necessary for the resolution of recombining mitochondrial genomes, and in Schizosaccharomyces pombe the homologous protein YDC2 is thought to have a similar function [4].
• The open reading frame of this gene has been cloned and the encoded protein, YDC2, expressed in E.coli . The purified recombinant YDC2 exhibits Holliday junction resolvase activity and is, therefore, a functional S.pombe homologue of CCE1 [1].
• Local disruption of DNA structure around the centre of the junction by CCE1 of Saccharomyces cerevisiae has been investigated using 2-aminopurine fluorescence [5].

Biological context of CCE1

• The sequence of a 9.3 kb segment located on the left arm of the yeast chromosome XI reveals five open reading frames including the CCE1 gene and putative products related to MYO2 and to the ribosomal protein L10 [6].
• The results indicate that binding of CCE1 results in a complete unpairing of the four central base-pairs of the junction, with a lesser disruption of the next base-pairs [5].

Associations of CCE1 with chemical compounds

• On binding CCE1, 2-aminopurine bases located at the point of strand exchange exhibit a large increase in fluorescence intensity (up to 39-fold enhancement), consistent with complete unstacking [5].

Other interactions of CCE1

• Since CCE1 is allelic to MGT1, a gene required for the highly biased transmission of petite mitochondrial DNA in crosses between rho+ and hypersuppressive rho- cells, it seems likely that the CCE1 endonuclease functions within mitochondria [7].

Analytical, diagnostic and therapeutic context of CCE1

• The CCE1 gene was cloned by PCR, and the expressed protein purified to homogeneity [8].

References