Modification of PCNA by ISG15 plays a crucial role in termination of error-prone translesion DNA synthesis.
In response to DNA damage, PCNA is mono-ubiquitinated and triggers translesion DNA synthesis (TLS) by recruiting polymerase-η. However, it remained unknown how error-prone TLS is turned off after DNA lesion bypass to prevent mutagenesis. Here we showed that ISG15 modification (ISGylation) of PCNA plays a key role in TLS termination. Upon UV irradiation, EFP, an ISG15 E3 ligase, bound to mono-ubiquitinated PCNA and promoted its ISGylation. ISGylated PCNA then tethered USP10 for deubiquitination and in turn the release of polymerase-η from PCNA. Eventually, PCNA was deISGylated by UBP43 for reloading of replicative DNA polymerases and resuming normal DNA replication. However, ISGylation-defective Lys-to-Arg mutations in PCNA or knockdown of any of ISG15, EFP, or USP10 led to persistent recruitment of mono-ubiquitinated PCNA and polymerase-η to nuclear foci, causing an increase in mutation frequency. These findings establish a crucial role of PCNA ISGylation in termination of error-prone TLS for preventing excessive mutagenesis.
School of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 151-742, South Korea.
Jung Mi
JM
Park
School of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 151-742, South Korea.
Seung Wook
SW
Yang
School of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 151-742, South Korea.
Kyung Ryun
KR
Yu
School of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 151-742, South Korea.
Seung Hyun
SH
Ka
School of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 151-742, South Korea.
Seong Won
SW
Lee
School of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 151-742, South Korea.
Jae Hong
JH
Seol
School of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 151-742, South Korea. Electronic address: gydbs98@snu.ac.kr.
Young Joo
YJ
Jeon
School of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 151-742, South Korea. Electronic address: chchung@snu.ac.kr.
Chin Ha
CH
Chung
D001120:Arginine / Q000378:metabolism; D001665:Binding Sites / Q000235:genetics; D016207:Cytokines / Q000235:genetics / Q000378:metabolism*; D004249:DNA Damage; D004257:DNA Polymerase II / Q000378:metabolism; D004260:DNA Repair; D004261:DNA Replication; D005786:Gene Expression Regulation; D055785:Gene Knockdown Techniques; D006367:HeLa Cells; D006801:Humans; D008239:Lysine / Q000378:metabolism; D016296:Mutagenesis; D059645:Mutation Rate; D018809:Proliferating Cell Nuclear Antigen / Q000235:genetics* / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D000070584:Tripartite Motif Proteins; D043222:Ubiquitin Thiolesterase / Q000235:genetics / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism; D054875:Ubiquitination; D014452:Ubiquitins / Q000235:genetics / Q000378:metabolism*
D016207:Cytokines; D018809:Proliferating Cell Nuclear Antigen; D014157:Transcription Factors; D000070584:Tripartite Motif Proteins; C431363:USP10 protein, human; D014452:Ubiquitins; C074034:ISG15 protein, human; D001120:Arginine; C084523:TRIM25 protein, human; D044767:Ubiquitin-Protein Ligases; D004257:DNA Polymerase II; D043222:Ubiquitin Thiolesterase; D008239:Lysine