Transcriptional Regulation by DNA Structural Transitions and Single-stranded DNA-binding Proteins
This extract was created in the absence of an abstract.
Excerpt
Proteins that bind to single-stranded DNA (SSBs) withhigh affinity have been purified and characterized fromseveral prokaryotes, eukaryotes, and their viruses (Chaseand Williams 1986). These SSBs bind stoichiometricallyand cooperatively to single-stranded DNA but without sequence specificity, lowering the melting temperature ofDNA. SSBs cover the transient single-stranded regions ofDNA that normally arise in vivo as a result of replication,recombination, and repair, thereby removing secondarystructures that result from these cellular processes and presenting the DNA in an extended conformation for interaction with proteins involved in DNA metabolism. Severallines of evidence indicate that SSBs are involved in a multitude of protein-protein interactions (Formosa et al. 1983;Falkenberg et al. 1997; Kelman et al. 1998; Kong andRichardson 1998; Sarov-Blat and Livneh 1998). Recently,a number of reports in the literature implicate both nonspecific and site-specific SSBs in transcriptional regulation.Examples of SSBs that regulate transcription are found inboth prokaryotes and eukaryotes. In most cases, not manydetails regarding such activation are known; however,some general characteristics emerge. Site-specific SSBsseem to be implicated in activation and repression in eukaryotes, whereas nonspecific SSBs have been found tohave a role in transcription activation in prokaryotes...
