A tumor necrosis factor alpha- and interleukin 6-inducible protein that interacts with the small subunit of DNA polymerase delta and proliferating cell nuclear antigen
H. He et al., A tumor necrosis factor alpha- and interleukin 6-inducible protein that interacts with the small subunit of DNA polymerase delta and proliferating cell nuclear antigen, P NAS US, 98(21), 2001, pp. 11979-11984
Citations number
36
Categorie Soggetti
Multidisciplinary
Journal title
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
A cDNA encoding a protein of 36 kDa, polymerase delta-interacting protein 1
(PDIP1), that interacts with the small subunit (p50) of DNA polymerase del
ta (pol delta) was identified in a two-hybrid screen of a HepG2 cDNA librar
y by using p50 as bait. The interaction of PDIP1 with p50 was confirmed by
pull-down assays, and a similar assay was used to demonstrate that PDIP1 in
teracts directly with the proliferating cell nuclear antigen (PCNA). PCNA a
nd p50 bound to PDIP1 simultaneously, and PDIP1 stimulated pol delta activi
ty in vitro in the presence, but not the absence, of PCNA, suggesting that
PDIP1 also interacts functionally with both p50 and PCNA. Subcellular local
ization studies demonstrated that PDIP1 is a nuclear protein that colocaliz
es with PCNA at replication foci. A putative PCNA-binding motif was identif
ied within the C terminus of PDIP1, and a synthetic peptide containing this
PCNA-binding motif was shown to bind PCNA by far-Western analysis. Norther
n analysis demonstrated that PDIP1 rnRNA is present in a wide variety of hu
man tissues. PDIP1 was found to be highly homologous to a previously identi
fied protein, B12 [Wolf, F. W., Marks, R. M., Sarma. V., Byers, M. G., Katz
, R. W., Shows, T. B. & Dixit, V. M. (1992) J. BioL Chem. 267,1317-1326], o
ne of the early response genes induced by tumor necrosis factor alpha. PDIP
1 synthesis can also be induced by tumor necrosis factor alpha and by IL-6,
cytokines essential for liver regeneration after loss of hepatic tissue. I
t is suggested that PDIP1 provides a link between cytokine activation and D
NA replication in liver as well as in other tissues.