Disease relevance of RpA-70

• Mitochondrial DNA polymerase from Drosophila embryos has been characterized with regard to its mechanism of DNA synthesis in the presence of single-stranded DNA-binding protein from Escherichia coli [1].

High impact information on RpA-70

• Nuclear import of RPA in Xenopus egg extracts requires a novel protein XRIPalpha but not importin alpha [2].
• Furthermore, we show that mutations of RPA at the cdc2 kinase site prevents RPA dissociation from chromatin and impairs mitotic chromosome assembly without affecting DNA replication [3].
• This function involves the recruitment to chromatin of cdc2 kinase and the chromatin disassembly of interphasic replication protein A (RPA) foci [3].
• Our results indicate that the stimulation of Drosophila DNA polymerase gamma by single-stranded DNA-binding protein results primarily from an increased rate of primer recognition and binding [1].
• The phosphorylation and localization of Drosophila melanogaster Replication Protein A (DRP-A) was examined during oogenesis and in single embryos during the syncytial nuclear divisions of embryogenesis [4].

Biological context of RpA-70

• Strikingly, in ovaries a relatively large amount of DRP-A was observed during the early mitotic stages of oogenesis [4].
• In contrast to other systems where a phosphorylated form of RP-A has been correlated with S phase, only the nonphosphorylated form of Drosophila RP-A is observed in early Drosophila embryos during DNA replication [4].
• Subsequently at mitosis, DRP-A becomes delocalized [4].
• Replication protein A (RP-A) is an essential single-stranded DNA binding protein (SSB) involved in the initiation and elongation phases of eukaryotic DNA replication [5].
• After this point, dm-RPA70 expression is downregulated in cells that enter a G1 phase and exit the mitotic cycle, becoming restricted to brief bursts of accumulation from late G1 to S phase [6].

Regulatory relationships of RpA-70

• D-SSB stimulates the extent and processivity of DNA synthesis of its cognate DNA polymerase alpha [7].

Analytical, diagnostic and therapeutic context of RpA-70

• Equilibrium titrations indicate that D-SSB binds with low cooperativity, omega = 10-300, and high apparent affinity, K omega = (0.7-5) x 10(7) M-1, at 225 mM NaCl [7].

References