Mediation of Proliferating Cell Nuclear Antigen (PCNA)-dependent DNA Replication through a Conserved p21Cip1-like PCNA-binding Motif Present in the Third Subunit of Human DNA Polymerase δ

Abstract DNA polymerase δ (Polδ) is a highly processive essential replicative DNA polymerase. In humans, the Polδ holoenzyme consists of p125, p50, p68 and p12 subunits and recently, we showed that the p12 subunit exists as a dimer. Extensive biochemical studies suggest that all the subunits of Polδ interact with the processivity factor proliferating cell nuclear antigen (PCNA) to carry out a pivotal role in genomic DNA replication. While PCNA-interacting protein motif (PIP) motifs in p68, p50 and p12 have been mapped, same in p125, the catalytic subunit of the holoenzyme, remains elusive. Therefore, in the present study by using multiple approaches we have conclusively mapped a non-canonical PIP motif from residues 999VGGLLAFA1008 in p125, which binds to the inter-domain-connecting loop (IDCL) of PCNA with high affinity. Collectively, including previous studies, we conclude that similar to Saccharomyces cerevisiae Polδ, each of the human Polδ subunits possesses motif to interact with PCNA and significantly contributes toward the processive nature of this replicative DNA polymerase.

Download Full-text

Human DNA Polymerase ε Colocalizes with Proliferating Cell Nuclear Antigen and DNA Replication Late, but Not Early, in S Phase

Journal of Biological Chemistry ◽

10.1074/jbc.m110615200 ◽

2001 ◽

Vol 277 (10) ◽

pp. 8658-8666 ◽

Cited By ~ 62

Author(s):

Jill Fuss ◽

Stuart Linn

Keyword(s):

Dna Replication ◽

Dna Polymerase ◽

Proliferating Cell Nuclear Antigen ◽

S Phase ◽

Nuclear Antigen ◽

Human Dna ◽

Proliferating Cell

Download Full-text

Fibroblast proliferation during myocardial development in rats is regulated by IGF-1 receptors

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1995.269.3.h943 ◽

1995 ◽

Vol 269 (3) ◽

pp. H943-H951 ◽

Cited By ~ 3

Author(s):

K. Reiss ◽

W. Cheng ◽

J. Kajstura ◽

E. H. Sonnenblick ◽

L. G. Meggs ◽

...

Keyword(s):

Dna Replication ◽

Dna Polymerase ◽

Proliferating Cell Nuclear Antigen ◽

Cardiac Fibroblasts ◽

Nuclear Antigen ◽

Dna Polymerase Alpha ◽

Myocardial Development ◽

Left And Right ◽

Proliferating Cell

To determine whether the growth of cardiac fibroblasts during development is modulated by the insulin-like growth factor (IGF)-1 receptor (IGF-1R), the expression of IGF-1, IGF-2, and IGF-1R was determined in fibroblasts from fetal and postnatal hearts. The expression of proliferating cell nuclear antigen (PCNA) and DNA polymerase-alpha was also evaluated in combination with the estimation of DNA replication. In comparison with fetal hearts, at postnatal day 21, fibroblast expression of IGF-1R mRNA, IGF-2, PCNA, and DNA polymerase-alpha was reduced by 77, 70, 80, and 86%, respectively. Moreover, IGF-1R protein decreased by 48% at 21 days. Bromodeoxyuridine labeling decreased by 88 and 89% in the left and right ventricle, respectively, at this time. Two different antisense oligodeoxynucleotides to IGF-1R reduced DNA replication by 60 and 44% in fibroblasts in culture. In addition, this intervention markedly attenuated the growth response of fibroblasts to IGF-1 or serum. In conclusion, the IGF-1R system appears to play a major role in the regulation of fibroblast growth in the heart in vivo.

Download Full-text