High-Frequency Gene Conversion between Repeated Cμ Sequences Integrated at the Chromosomal Immunoglobulin μ Locus in Mouse Hybridoma Cells

Abstract

The occurrence of mitotic recombination between repeated immunoglobulin mu gene constant (Cμ) region sequences stably integrated at the haploid chromosomal immunoglobulin μ locus in murine hybridoma cells was investigated. Recombination events are detected as changes in hapten-specific immunoglobulin M production. Recombination occurs with high frequency (0.5 to 0.8%) by a mechanism consistent with gene conversion. A double-strand break repair-like mechanism is suggested by the finding that repair of a 2-bp deletion mutation and a 2-bp insertion mutation occurs with parity in a donor-directed manner. The results also suggest that the gene conversion process is directional in that the 5′ Cμ region sequence is preferentially converted.