Transcription factors in DNA replication.

Accumulating evidence suggests the involvement of transcription factors in the regulation of DNA replication in eukaryotic cells. Almost all eukaryotic DNA viruses contain binding sites for transcription factors which function as auxiliary elements for DNA replication initiation at replication origins, and, indeed, the binding of transcription factors to these elements has been shown to stimulate DNA replication. Transcription factors also regulate some of the chromosome DNA replication origins of budding yeast, indicating that transcription factor involvement in DNA replication is not restricted to viruses. Consistent with this notion, recently determined replication origins of higher eukaryotes have been found occasionally to associate with transcription factor binding sites, although there is no direct evidence for the involvement of the factors that bind to these sequences in DNA replication. Analyses using viral and yeast systems have suggested that transcription factors stimulate the formation of the replication initiation complex by engaging in specific interactions with proteins of the initiation complex and/or by modulating the repressive chromatin structure around origins of replication. These mechanisms are analogous to those advanced to explain stimulation of transcription by transcription factors. The accumulated data suggests that transcription factors play a general role in the formation of functional complexes on chromosomes.