Interaction between human topoisomerase I and a novel RING finger/arginine-serine protein

Paul Haluska, Ahamed Saleem, Zeshaan Rasheed, Farheena Ahmed, Emily W. Su, Leroy F. Liu, Eric H. Rubin

Research output: Contribution to journalArticlepeer-review

71 Scopus citations


The N-terminus of human topoisomerase I participates in the binding of this enzyme to helicases and other proteins. Using the N-terminal 250 amino acids of human topoisomerase I and a yeast two-hybrid/ in vitro binding screen, a novel arginine-serine-rich peptide was identified as a human topoisomerase I-binding protein. The corresponding full-length protein, named topors, contains a consensus RING zinc finger domain and nuclear localization signals in addition to the arginine-serine-rich region. The RING finger domain of topors is homologous to a similar domain in a family of viral proteins that are involved in the regulation of viral transcription. When expressed in HeLa cells as a green fluorescent protein fusion, topors localizes in the nucleus in a punctate pattern and co-immunoprecipitates with topoisomerase I. These data suggest that topors is involved in transcription, possibly recruiting topoisomerase I to RNA polymerase II transcriptional complexes.

Original languageEnglish (US)
Pages (from-to)2538-2544
Number of pages7
JournalNucleic acids research
Issue number12
StatePublished - Jun 15 1999

ASJC Scopus subject areas

  • Genetics


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