Human ribosomal protein S3 (hRpS3) interacts with uracil-DNA glycosylase (hUNG) and stimulates its glycosylase activity

Sung Il Ko, Jong Hwa Park, Min Ju Park, Joon Kim, Lin Woo Kang, Ye Sun Han

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14 Citations (Scopus)


Human ribosomal protein S3 (hRpS3) is a small ribosomal subunit showing apurinic/apyrimidinic (AP) lyase activity and has been suggested to play a role in the cellular DNA-damage response pathway. However, the functional interactions between hRpS3 and other base excision repair (BER) DNA glycosylases have not been reported. We identified, for the first time, the interaction between hRpS3 and human uracil-DNA glycosylase (hUNG) and investigated the functional consequences of this interaction. hRpS3 was shown to interact with hUNG in co-immunoprecipitation assay using transiently transfected HEK293 cells and GST pull-down assay using microbial expression systems. In an assay using a 5′-end-radiolabeled 39-mer oligonucleotide duplex containing a U/G mismatch, hRpS3 dramatically stimulated the uracil-excision activity of hUNG, whereas hRpS3 alone had no cleavage activity. Pre-incubation of hRpS3 with the U/G mismatch containing DNA duplex also increased the hUNG uracil-excision activity; however, hRpS3 did not increase the DNA binding activity of hUNG in a trapping assay of hUNG and the U/G mismatch containing DNA duplex using UV cross-linking. hRpS3 has been suggested to stimulate the uracil-excision activity of hUNG by enhancing its dissociation from AP sites and increasing its turn-over rate. The disruption of hRpS3 by small-interfering RNA (siRNA-hRpS3) transfection reduced the uracil-excision activity preserved in cell extracts, whereas the supplement of purified hRpS3 retained uracil-excision activity. These results strongly suggest that hRpS3 may be involved in the uracil-excision pathway, probably by participating in the DNA repair mechanism to remove uracil generated by the deamination of cytosine in DNA, and by preventing C/G → T/A transition mutations.

Original languageEnglish
Pages (from-to)54-64
Number of pages11
JournalMutation Research - Fundamental and Molecular Mechanisms of Mutagenesis
Issue number1-2
Publication statusPublished - 2008 Dec 15

Bibliographical note

Funding Information:
This work was supported by National Research Laboratory Program (M10400000046-04J0000-04610), Korea Research Foundation Grant (Grant KRF-2006-005-J03403) of Korea government, the Real Time Molecular Imaging Project of the Korea Ministry of Science and Technology, and BioGreen21 program (20070501034003) of the Korea Rural Development Administration.


  • Excision activity
  • Human ribosomal protein S3
  • Human uracil-DNA glycosylase
  • Uracil

ASJC Scopus subject areas

  • Molecular Biology
  • Genetics
  • Health, Toxicology and Mutagenesis


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