High impact information on RAD55

• We observed chromosome fusions only in mutant strains expressing Rad51 and Rad55 or when Tel1 was inactivated [1].
• By several independent criteria, RAD55- and RAD57-encoded products are shown here to exist as a stable heterodimer, with a dissociation constant of <2 x 10(-10) M [2].
• Phosphorylation of rad55 on serines 2, 8, and 14 is required for efficient homologous recombination in the recovery of stalled replication forks [3].
• Rad55 is a Rad51 paralog in Saccharomyces cerevisiae and functions in the assembly of the Rad51 filament, a central intermediate in recombinational DNA repair [3].
• In contrast, rad51-K191A, a mutation that abolishes recombination and results in a protein that does not bind to single-stranded DNA (ssDNA), supports adaptation, as do Rad51 mutants impaired in interaction with Rad54p or Rad55p [4].

Biological context of RAD55

• A class of rad51 alleles was isolated that suppresses the requirement for RAD55 and RAD57 in DNA repair, but not the other accessory factors [5].
• We now report that gene conversion is also abolished when RAD54, RAD55, and RAD57 are deleted but BIR occurs, as with rad51Delta cells [6].
• These phenotypes were enhanced at low temperatures, similar to deletions in the S. cerevisiae RAD55 and RAD57 genes [7].
• Since all four alleles of RAD55 are temperature conditional (cold sensitive) for their radiation phenotype, we investigated the phenotype produced by null mutations in the RAD55 gene, constructed in vitro and transplaced to the yeast chromosome [8].
• Characterization of null mutants of the RAD55 gene of Saccharomyces cerevisiae: effects of temperature, osmotic strength and mating type [8].

Associations of RAD55 with chemical compounds

• RAD55 and RAD57 contain putative nucleotide binding motifs, and the importance of these motifs was determined by constructing site-directed mutations of the conserved lysine residue within the Walker A-box [9].
• Rad55p was specifically phosphorylated in response to DNA damage induced by the alkylating agent methyl methanesulfonate, dependent on an active DNA damage checkpoint [10].
• However, the function of Esc4 does not appear to be restricted to a Rad55-dependent process, as we observed an increase in sensitivity to the DNA alkylating agent methane methylsulfonate (MMS) in a esc4Deltarad55Delta mutant, as well as in double mutants of esc4Delta and other recombination genes, compared to the corresponding single mutants [11].

Other interactions of RAD55

• Functional differences and interactions among the putative RecA homologs Rad51, Rad55, and Rad57 [9].
• Different Mating-Type-Regulated Genes Affect the DNA Repair Defects of Saccharomyces RAD51, RAD52 and RAD55 Mutants [12].
• Dun1 is required for DNA damage-induced transcription of certain target genes, transient G(2)/M arrest after DNA damage, and DNA damage-induced phosphorylation of the DNA repair protein Rad55 [13].

References