Long Interspersed Nuclear Element (LINE) Mediated Genomic Instability

We have isolated and characterized a novel human homeobox gene designated Mix. 1 homeobox Xenopus laevis-like gene 2 MIXL2, as a gene that contains a repetitive element in its 3 UTR MER22. The MIXL2 gene encodes a predicted 232 amino acid open reading frame, which contains a highly conserved mix. 1-like homeobox and an acidic motif Radiation hybrid mapping and Fluorescence in situ hybridization localize the MIXL2 gene to human chromosome 1q32-41, a region of gain in breast tumors. Consistent with these cytogenetic findings we detected allelic imbalance for loci flanking MIXL2 in 1425 primary breast tumors. Additionally, a search of the human dbEST database suggested a highly restricted expression as we detected only three EST clones one each from normal germinal center B cell, undifferentiated germ cell tumor, and infiltrating ductal carcinoma of the breast. These findings suggest MTL2 may play a role in development and mammary carcinogenesis.