Rad51 expression and localization in B cells carrying out class switch recombination.

Localization of splenic B cells activated for switch recombination by in situ hybridization with Igamma1 switch transcript and Rad51 probes.

B cells are activated for switch recombination by signals from Th cells, but the site at which this first occurs in vivo has yet to be identified. By in situ hybridization of splenic sections using riboprobes specific for the Igamma1 switch transcript and Rad51 mRNA, we have visualized B cells that are newly activated for switch recombination and characterized the spatial and temporal patterns ...

onychomadesis in a patient with immunoglobulin class switch recombination deficiency

immunoglobulin class switch recombination deficiencies (ig csr deficiencies) or hyper igm syndromes (higm) are a group of primary immunodeficiency diseases, characterized by defective cd40 signaling of b cells resulting into a csr and a somatic hypermutation. the affected patients are characterized with reduced serum levels of igg and iga, and normal or elevated level of igm, which lead to incr...

Interallelic Class Switch Recombination

Genomic instability, endoreduplication, and diminished Ig class-switch recombination in B cells lacking Nbs1.

Mre11, Rad50, and Nbs1 form an evolutionarily conserved protein complex (Mre11-Rad50-Nbs1, MRN) that has been proposed to function as a DNA damage sensor. Hypomorphic mutations in Mre11 and Nbs1 result in the human ataxia-telangiectasia-like disorder and Nijmegen breakage syndrome (NBS), respectively. In contrast, complete inactivation of Mre11, Rad50, or Nbs1 leads to early embryonic lethality...

Altered kinetics of nonhomologous end joining and class switch recombination in ligase IV–deficient B cells

Immunoglobulin heavy chain class switch recombination (CSR) is believed to occur through the generation and repair of DNA double-strand breaks (DSBs) in the long and repetitive switch regions. Although implied, the role of the major vertebrate DSB repair pathway, nonhomologous end joining (NHEJ), in CSR has been controversial. By somatic gene targeting of DNA ligase IV (Lig4; a key component of...