Expression pattern analysis of transcribed HERV sequences is complicated by ex vivo recombination

Research output: Contribution to journalArticle


Background: The human genome comprises numerous human endogenous retroviruses ( HERVs) that formed millions of years ago in ancestral species. A number of loci of the HERV-K(HML-2) family are evolutionarily much younger. A recent study suggested an infectious HERV-K(HML-2) variant in humans and other primates. Isolating such a varian t from human individuals would be a significant finding for human biology. Results: When investigating expression patterns of specific HML-2 proviruses we encountered HERV-K(HML-2) cDNA sequences without proviral homologues in the human genome, named HERV-KX, that could very well support recently suggested infectious HML-2 variants. However, detailed sequence analysis, using the software RECCO, suggested that HERV-KX sequences were produced by recombination, possibly arising ex vivo, between transcripts from different HML-2 proviral loci. Conclusion: As RT-PCR probably will be instrumental for isolating an infectious HERV-K(HML2) variant, generation of "new" HERV-K(HML-2) sequences by ex vivo recombination seems inevitable. Further complicated by an unknown amount of allelic sequence variation in HERV-K(HML-2) proviruses, newly identified HERV-K(HML-2) variants should be interpreted very cautiously.


  • Aline Flockerzi
  • Jochen Maydt
  • Oliver Frank
  • Alessia Ruggieri
  • Esther Maldener
  • Wolfgang Seifarth
  • Patrik Medstrand
  • Thomas Lengauer
  • Andreas Meyerhans
  • Christine Leib-Moesch
  • Eckart Meese
  • Jens Mayer
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Pharmacology and Toxicology
Original languageEnglish
Publication statusPublished - 2007
Publication categoryResearch

Bibliographic note

The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Molecular Virology (013212007)