Disease relevance of mtSSB

• The remainder of this paper focuses on one of these cDNAs which encodes a Dm protein displaying significant sequence homology to Escherichia coli ssDNA-binding protein (SSB, involved in DNA replication, repair and recombination), as well as eukaryotic SSBs isolated from the mitochondria (mt) of rats, frogs, humans and yeast [1].

High impact information on mtSSB

• Overexpression of mtSSB restores cell growth rate and the copy number of mtDNA, whereas overexpression of a DNA-binding and functionally impaired form of mtSSB neither rescues the cell growth defect nor the mtDNA depletion phenotype [2].
• Mitochondrial single-stranded DNA-binding protein is required for mitochondrial DNA replication and development in Drosophila melanogaster [3].
• Our data suggest strongly that the Drosophila mtSSB gene is regulated by the DRE/DREF system [4].
• The D. melanogaster mtSSB gene contains four exons and three small introns [4].
• Regulation of mitochondrial single-stranded DNA-binding protein gene expression links nuclear and mitochondrial DNA replication in drosophila [4].

Biological context of mtSSB

• The deduced amino acid sequence shows the highest homology with the Xenopus laevis protein and the lowest with the Drosophila mtSSB [5].
• RNA- and single-stranded DNA-binding (SSB) proteins expressed during Drosophila melanogaster oogenesis: a homolog of bacterial and eukaryotic mitochondrial SSBs [1].
• In mammalian cell cultures, retinol supplementation-induced DNA double-strands breaks (DSB) and single-strands breaks (SSB), cell cycle progression and proliferative focus formation in terminal-differentiated rat Sertoli cells and increased DNA fragmentation in Chinese hamster lung fibroblasts (V79 cells), as measured by the comet assay [6].

Regulatory relationships of mtSSB

• The recombinant holoenzyme contains DNA polymerase and 3'-5' exonuclease that are stimulated substantially by both salt and mitochondrial single-stranded DNA-binding protein [7].

Analytical, diagnostic and therapeutic context of mtSSB

• In situ hybridization analysis shows that maternally deposited mtSSB mRNA is distributed homogeneously in the early embryo, whereas de novo transcript is produced specifically at an elevated level in the developing midgut [4].
• Three-dimensional structures of several B30.2/SPRY domain-containing proteins have been reported recently: murine SSB-2 in solution by NMR spectroscopy, a Drosophila SSB (GUSTAVUS), and human PRYSPRY protein by X-ray crystallography [8].

References