Chromosomal localization of the human gene encoding c-myc promoter- binding protein (MPB1) to chromosome 1p35-pter

We report the mapping of the human gene MPB1 (c-myc promoter binding protein), a recently identified gene regulatory protein. MPB1 binds to the c- myc P2 promoter and exerts a negative regulatory role on c-myc transcription. Since exogenous expression from transfection of the MPB1 gene suppresses the tumorigenic property of breast cancer cells, there was interest in determining the chromosomal location of this gene. The human MPB1 gene was assigned to human chromosome 1p35-pter using Southern blot analyses of genomic DNAs from rodent-human somatic hybrid cell lines. A specific human genomic fragment was observed only in the somatic cell lines containing human chromosome 1 or the p35-pter region of the chromosome.