DNA ligase I is recruited to sites of DNA replication by an interaction with proliferating cell nuclear antigen: identification of a common targeting mechanism for the assembly of replication factories.
In mammalian cells, DNA replication occurs at discrete nuclear sites termed replication factories. Here we demonstrate that DNA ligase I and the large subunit of replication factor C (RF-C p140) have a homologous sequence of approximately 20 amino acids at their N-termini that functions as a replication factory targeting sequence (RFTS). This motif consists of two boxes: box 1 contains the sequence IxxFF whereas box 2 is rich in positively charged residues. N-terminal fragments of DNA ligase I and the RF-C large subunit that contain the RFTS both interact with proliferating cell nuclear antigen (PCNA) in vitro. Moreover, the RFTS of DNA ligase I and of the RF-C large subunit is necessary and sufficient for the interaction with PCNA. Both subnuclear targeting and PCNA binding by the DNA ligase I RFTS are abolished by replacement of the adjacent phenylalanine residues within box 1. Since sequences similar to the RFTS/PCNA-binding motif have been identified in other DNA replication enzymes and in p21(CIP1/WAF1), we propose that, in addition to functioning as a DNA polymerase processivity factor, PCNA plays a central role in the recruitment and stable association of DNA replication proteins at replication factories.
Montecucco
A
A
Istituto di Genetica Biochimica ed Evoluzionistica CNR, Italy.
Rossi
R
R
Levin
D S
DS
Gary
R
R
Park
M S
MS
Motycka
T A
TA
Ciarrocchi
G
G
Villa
A
A
Biamonti
G
G
Tomkinson
A E
AE
D000595:Amino Acid Sequence; D001665:Binding Sites; D002461:Cell Line, Transformed; D000072481:DNA Ligase ATP; D011088:DNA Ligases / Q000235:genetics / Q000378:metabolism*; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D018398:Homeodomain Proteins; D006801:Humans; D015778:Minor Histocompatibility Antigens; D008969:Molecular Sequence Data; D019913:Nuclear Localization Signals; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D051818:Replication Protein C; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins
C096816:BCL2-related protein A1; D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; C000607892:LIG1 protein, human; C096063:MATA1 protein, S cerevisiae; D015778:Minor Histocompatibility Antigens; D019913:Nuclear Localization Signals; D018809:Proliferating Cell Nuclear Antigen; D019253:Proto-Oncogene Proteins c-bcl-2; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D051818:Replication Protein C; D011088:DNA Ligases; D000072481:DNA Ligase ATP