DIFFERENTIAL GENE-EXPRESSION IN MAMMARY-CARCINOMA CELL-LINES - IDENTIFICATION OF DRIM, A NEW GENE DOWN-REGULATED IN METASTASIS

Differential display technique was applied to a pair of cell lines der ived fi om human breast carcinoma cell line MDA-MB. 435 with metastati c and non-metastatic properties in the nude mouse system, with the obj ective to isolate genes involved in metastasis. DRIM (Down-Regulated I n Metastasis) was the only gene found to be differentially expressed i n this system. DRIM encodes a protein comprising 2785 amino acids with significant homology to a protein in yeast and C elegans. The protein contains a conserved positively charged tail and several HEAT repeats , designated after four functionally characterized proteins in which t he repeat was detected Most of the hydrophobic regions of DRIM can be assigned to HEAT repeats. Expression of DRIM at the RNA level was inve stigated in several normal tissues and tumor cell lines.