The RNF8/RNF168 ubiquitin ligase cascade facilitates class switch recombination

Shaliny Ramachandran, Richard Chahwan, Rajeev M. Nepal, Darina Frieder, Stephanie Panier, Sergio Roa, Ahmad Zaheen, Daniel Durocher, Matthew D. Scharff, Alberto Martin

Research output: Contribution to journalArticlepeer-review

59 Scopus citations


An effective immune response requires B cells to produce several classes of antibodies through the process of class switch recombination (CSR). Activation-induced cytidine deaminase initiates CSR by deaminating deoxycytidines at switch regions within the Ig locus. This activity leads to double-stranded DNA break formation at the donor and recipient switch regions that are subsequently synapsed and ligated in a 53BP1-dependent process that remains poorly understood. The DNA damage response E3 ubiquitin ligases RNF8 and RNF168 were recently shown to facilitate recruitment of 53BP1 to sites of DNA damage. Here we show that the ubiquitination pathway mediated by RNF8 and RNF168 plays an integral part in CSR. Using the CH12F3-2 mouse B cell line that undergoes CSR to IgA at high rates, we demonstrate that knockdown of RNF8, RNF168, and 53BP1 leads to a significant decrease in CSR. We also show that 53BP1-deficient CH12F3-2 cells are protected from apoptosis mediated by the MDM2 inhibitor Nutlin-3. In contrast, deficiency in either E3 ubiquitin ligase does not protect cells from Nutlin-3-mediated apoptosis, indicating that RNF8 and RNF168 do not regulate all functions of 53BP1.

Original languageEnglish (US)
Pages (from-to)809-814
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number2
StatePublished - 2010


  • 53BP1
  • Activation-induced cytidine deaminase
  • DNA damage response

ASJC Scopus subject areas

  • General


Dive into the research topics of 'The RNF8/RNF168 ubiquitin ligase cascade facilitates class switch recombination'. Together they form a unique fingerprint.

Cite this