Ubc13 dosage is critical for immunoglobulin gene conversion and gene targeting in vertebrate cells.
In contrast to lower eukaryotes, most vertebrate cells are characterized by a moderate efficiency of homologous recombination (HR) and limited feasibility of targeted genetic modifications. As a notable exception, the chicken DT40 B cell line is distinguished by efficient homology-mediated repair of DNA lesions during Ig gene conversion, and also shows exceptionally high gene-targeting efficiencies. The molecular basis of these phenomena is elusive. Here we show that the activity levels of Ubc13, the E2 enzyme responsible for non-canonical K63-linked polyubiquitination, are critical for high efficiency of Ig gene conversion and gene targeting in DT40. Ubc13(+/-) cells show substantially lower homology-mediated repair, yet do not display changes in somatic hypermutation, overall DNA repair or cell proliferation. Our results suggest that modulation of the activity of K63-linked polyubiquitination may be used to customize HR efficiencies in vertebrate cells.
Ertongur
Isin
I
Institute of Clinical Molecular Biology, Helmholtz Center Munich, German Research Center for Environmental Health, Munich, Germany.
Tomi
Nils-Sebastian
NS
Kutzera
André
A
Fischer-Burkart
Sabine
S
Jungnickel
Berit
B
D000818:Animals; D002460:Cell Line; D002645:Chickens / Q000235:genetics; D005785:Gene Conversion; D018390:Gene Targeting; D005803:Genes, Immunoglobulin; D006579:Heterozygote; D044763:Ubiquitin-Conjugating Enzymes / Q000235:genetics*
D044763:Ubiquitin-Conjugating Enzymes