Cutting Edge: DNA Polymerases μ and λ Are Dispensable for Ig Gene Hypermutation

Abstract

Mutations arising in Ig V genes during an immune response are most likely introduced by one or several error-prone DNA polymerases. Many of the recently described nonreplicative DNA polymerases have an intrinsic fidelity compatible with such an activity, the strongest candidates being polymerase (pol) η, pol ι, pol ζ, and pol μ. We report in this work that mice inactivated for either of the two polymerases related to pol β (i.e., pol μ and pol λ) are viable and fertile and display a normal hypermutation pattern.