The human DNA polymerase lambda interacts with PCNA through a domain important for DNA primer binding and the interaction is inhibited by p21/WAF1/CIP1.
In this paper we show that DNA polymerase lambda (pol lambda) interacts with proliferating cell nuclear antigen (PCNA) in vivo in human cells. Moreover, by using recombinant mutated PCNA, we could demonstrate that pol lambda interacts with both the interdomain-connecting loop and the nearby hydrophobic pocket on the anterior of PCNA and that critical residues within a helix-hairpin-helix domain of pol lambda, important for proper DNA primer binding, are also involved in the enzyme's interaction with PCNA. Finally, we show that the tumor suppressor protein p21(WAF1/CIP1) can efficiently compete in vitro with pol lambda for binding to PCNA. Given the high rate of frameshift mutations induced by pol lambda and its ability to bypass abasic sites, accurate regulation of pol lambda activity by PCNA and p21 concerted action might be important for preventing genetic instability.
Maga
Giovanni
G
Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche, Pavia, Italy. maga@igm.cnr.it
Blanca
Giuseppina
G
Shevelev
Igor
I
Frouin
Isabelle
I
Ramadan
Kristijan
K
Spadari
Silvio
S
Villani
Giuseppe
G
Hübscher
Ulrich
U
D001665:Binding Sites; D001667:Binding, Competitive; D018797:Cell Cycle Proteins / Q000378:metabolism*; D050759:Cyclin-Dependent Kinase Inhibitor p21; D019951:DNA Polymerase beta / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017931:DNA Primers / Q000378:metabolism*; D006801:Humans; D047468:Immunoprecipitation; D009154:Mutation; D018809:Proliferating Cell Nuclear Antigen / Q000737:chemistry / Q000378:metabolism*; D017434:Protein Structure, Tertiary
C493956:CDKN1A protein, human; D018797:Cell Cycle Proteins; D050759:Cyclin-Dependent Kinase Inhibitor p21; D017931:DNA Primers; D018809:Proliferating Cell Nuclear Antigen; C415367:DNA polymerase beta2; D019951:DNA Polymerase beta