Comment on "Uracil DNA Glycosylase Activity Is Dispensable for Immunoglobulin Class Switch"

Publisher Website
Google Scholar
Abstract
Begum et al.(6) argue that UNG catalytic activity cannot be involved in the formation of DSBs because, when they ectopically expressed three catalytically crippled forms of UNG in UNG–/– B cells, DSBs and overall CSR were observed [UNG–/– B cells have previously been found deficient in the formation of DSBs and CSR (7).]. However, the three UNG single mutants—D145N, N204V, and H268L—are still very powerful catalysts and can excise uracil from duplex DNA with a half-life of about 1 min (8, 9). This residual activity may be sufficient to give rise to DSBs at a rate comparable to, or faster than, the subsequent steps in CSR.