Mt. Armentero et al., TARGETING OF DNA-POLYMERASE TO THE ADENOVIRUS ORIGIN OF DNA-REPLICATION BY INTERACTION WITH NUCLEAR FACTOR-I, Proceedings of the National Academy of Sciences of the United Statesof America, 91(24), 1994, pp. 11537-11541
Efficient initiation by the DNA polymerase of adenovirus type 2 requir
es nuclear factor I(NFI), a cellular sequence-specific transcription f
actor. Three functions of NFI-dimerization, DNA binding, and activatio
n of DNA replication-are colocalized within the N-terminal portion of
the protein. To define more precisely the role of NFI in viral DNA rep
lication, a series of site directed mutations within the N-terminal do
main have been generated, thus allowing the separation of all three fu
nctions contained within this region. Impairment of the dimerization f
unction prevents sequence-specific DNA binding and in turn abolishes t
he NFI-mediated activation of DNA replication. NFI DNA-binding activit
y, although necessary, is not sufficient to activate the initiation of
adenovirus replication. A distinct class of NFI mutations that abolis
h the recruitment of the viral DNA polymerase to the origin also preve
nt the activation of replication. Thus, a direct interaction of NFI wi
th the viral DNA polymerase complex is required to form a stable and a
ctive preinitiation complex on the origin and is responsible for the a
ctivation of replication by NFI.