ASSIGNMENT OF THE HUMAN MAD AND MXI1 GENES TO CHROMOSOMES 2P12-P13 AND 10Q24-Q25

MAD and MXI1, two recently described members of the basic helix-loop-h elix (bHLH) gene family, encode proteins that dimerize with and modula te the DNA binding of max. In turn, mad-max or mxi1-max heterodimers o r max homodimers can compete for DNA binding sites with dimers formed between max and myc oncoproteins and antagonize the transcriptional ac tivities of this latter class of proteins. Using a combination of soma tic cell mapping and fluorescence in situ hybridization techniques, we have determined the chromosomal locations of the MAD and MXI1 genes. The MAD gene maps to chromosome 2p12-p13, a region involved in translo cations and deletions in acute and chronic lymphocytic leukemias as we ll as nonlymphocytic leukemias and Hodgkin disease. The MXI1 gene loca lizes to chromosome 10q24-q25, a region involved in translocations and deletions in acute and chronic lymphocytic leukemias and prostatic ca rcinomas. The availability of genomic clones of MAD and MXI1 will perm it an assessment of their involvement in these diseases at the molecul ar level. (C) 1994 Academic Press, Inc.