ACTIVATION OF A NOVEL GENE IN 3Q21 AND IDENTIFICATION OF INTERGENIC FUSION TRANSCRIPTS WITH ECOTROPIC VIRAL INSERTION SITE-I IN LEUKEMIA

We have identified a novel gene, GR6, located within the leukemia brea kpoint region of 3q21, that is normally expressed in early fetal devel opment but not in adult peripheral blood. GR6 is activated in the UCSD -AML1 cell line and in a leukemic sample, both of which carry a t(3;3) (q21;q26). In UCSD-AML1, we have also identified fusion transcripts be tween the ecotropic viral insertion site I(EVI1) gene in 3q26 and GR6 and between EVI1 and Ribophorin I that maps 30 kb telomeric to GR6 in 3q21, All fusions splice the 5' ends of the 3q21 genes into exon 2 of the EVI1 gene, an event that is similar to the normal intergenic splic ing of MDS1-EVI1 and to those previously documented in leukemias with t(3;21) and t(3;12), in which acute myelogenous leukemia 1-EVI1 fusion s and ETV6-EVI1 fusions, respectively, occur. The Ribophorin I-EVI1 fu sion in particular may be a common occurrence in t(3;3).