DNA Replication: A Cluster Linking a Hypothetical to the ruvABC Genes

Here is a short description of the function of the ruvABC genes and the rolw they play in replication (from Comparative and Evolutionary Analysis of the Bacterial Homologous Recombination Systems by Rocha, Cornet, and Michel):
In E. coli, the joint molecules formed by RecA are resolved by either the RuvABC complex or, in an unknown way, by the action of the RecG helicase. The RuvAB and RuvC proteins catalyze the branch migration and the resolution of Holliday junction recombination intermediates, respectively. These three proteins are thought to interact in a resolvasome complex, in which a RuvABC-junction complex tracks along DNA, with RuvC able to scan for cleavable sequences as the DNA passes through.


Now, look at the following cluster. Note that

  1. the green genes numbered 2 encode Holliday junction DNA helicase RuvA,
  2. the blue genes numbered 3 encode Holliday junction DNA helicase RuvB,
  3. the purple genes numbered 4 encode Crossover junction endodeoxyribonuclease ruvC (EC 3.1.22.4).


Look at the co-occurrences of these three genes with the red genes numbered 1. It is clear that this uncharacterized gene numbered 1 is closely related to the ruvABC genes. Note that in E.coli the three ruvABC genes do not occur in a single operon -- an inserted gene has separated ruvC from ruvAB. Since the gene we are considering remains close to ruvC and the two genes tend to be adjacent in many genomes, I would be tempted to conjecture that the red genes play a role closely related to ruvC.

That may be reaching too far.