Genetic Mapping and Allelic Loss Analysis in Mouse Thymic Lymphomas of Helios and Aiolos Belonging to the Ikaros Gene Family

The Ikaros gene undergoes bi‐allelic changes at a high frequency in γ‐ray‐induced mouse thymic lymphomas, suggesting the relevance of Ikaros to the lymphoma development. Here we test whether Helios and Aiolos, two other members of the Ikaros gene family, are also involved in lymphomagenesis. Genetic mapping showed that Helios is located between D1Mit531 and D1Mit19 on chromosome 1 and Aiolos is between D11Mit222 and D11Mit332 on chromosome 11. Analysis using polymorphic markers around the two regions revealed that neither locus exhibited allelic loss in the 78 lymphomas that were induced in (p)53 wild‐type mice, whereas in 102 (p)53(KO/+) mouse‐derived lymphomas Helios and Aiolos loci showed allelic loss in 8% (8/102) and 33% (34/102), respectively. However, 33 of the 34 lymphomas showing allelic loss at Aiolos were/j53(KO/‐) and were accompanied by loss of the (p)53 wild‐type allele on the same chromosome. Homozygous deletion and mutation analyses failed to detect bi‐allelic alterations. These results do not suggest any obvious contribution of Helios or Aiolos to oncogenesis of the mouse thymic lymphomas.