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A direct interaction between a DNA‐tracking protein and a promoter recognition protein: implications for searching DNA sequence.
Author(s) -
TinkerKulberg R. L.,
Fu T. J.,
Geiduschek E. P.,
Kassavetis G. A.
Publication year - 1996
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1996.tb00883.x
Subject(s) - tinker , biology , library science , genetics , computer science , sociology , anthropology
Bacteriophage T4 gene 45 protein, gp45, serves as the sliding clamp of viral DNA replication and as the activator of T4 late gene transcription. In the latter context, DNA tracking is an essential feature of the unique mechanism of action. T4 late promoters, which consist of a simple TATA box, TATAAATA, are recognized by the small sigma‐family gene 55 protein, gp55, which binds to Escherichia coli RNA polymerase core. A direct and RNA polymerase‐independent interaction of gp45 with gp55 has been demonstrated in two ways. (i) gp45 tracks along DNA; co‐tracking of gp55 requires the previously documented DNA‐loading process of gp45, and can be detected by photochemical crosslinking. (ii) The dynamics of DNA tracking by gp45 can be followed by footprinting; the catenated DNA‐tracking state of gp45 is short‐lived, but is stabilized by gp55. The ability of this topologically linked DNA‐tracking transcriptional activator to interact directly with a promoter recognition protein suggests the existence of multiple pathways of promoter location, which are discussed.