T-cell receptor-γ rearrangement and c-myb methylation in MNNG-exposed Bloom syndrome B-lymphoblastoid cells

The MNNG-exposed Bloom syndrome (BS) B-lymphoblastoid cell population (BS-MNNG), when analyzed for aberrant genetic variations, showed an illegitimate rearrangement at the TCR-γ gene and hypermethylation at the c-myb protooncogene. The TCR-γ rearrangement involved a Vγ9 segment corresponding to a 4 kb band detected with a Jγ-specific probe in HindIII-digested DNA samples from BS-MNNG cells only. These variations were not shown by unexposed BS cells or both MNNG-exposed and unexposed normal (GA3) B-lymphoblastoid cells.