THE INACTIVATION OF THE XP-C GENE DOES NOT AFFECT SOMATIC HYPERMUTATION OR CLASS SWITCH RECOMBINATION OF IMMUNOGLOBULIN GENES

The mechanism of somatic hypermutation of immunoglobulin genes is not known, but appears to be linked to transcription and perhaps DNA repai r. In order to determine if global DNA repair or the repair of the non transcribed DNA strand is required for somatic mutation, we have analy sed mice whose XP-C gene was inactivated by homologous recombination. Our study shows that hypermutation occurs in XP-C knockout mice with a normal frequency, suggesting that the XP-C gene product is not requir ed for somatic hypermutation. Furthermore, we found that Ig gene switc h recombination also is normal in these mice. (C) 1997 Elsevier Scienc e Ltd.