MODULATION OF THE EXPRESSION OF THE RABBIT GALECTIN-3 GENE BY P53 ANDC-HA-RAS PROTEINS AND PMA

Galectin-3 is a galactose-binding lectin that has been found in severa l mammalian tissues, Galectin-3 gene is expressed in a wide range of n ormal and tumoral cells, In the case of myeloid cells, its expression correlates with the differentiation of monocytes to macrophages, In th e case of cancer cell lines, its expression correlates with tumorigeni city and metastatic potential, The regulation of the expression of thi s gene is still largely unknown, The rabbit galectin-3 gene has been i solated and characterized, Its structure revealed an organization simi lar to that of the murine galectin-3 gene, The genomic sequences locat ed upstream from its 5' end, upon insertion upstream from a promoter-f ree reporter gene, exhibited a strong promoter activity, This activity was upregulated upon treatment of transfected smooth muscle cells wit h phorbol 12-myristate 13-acetate (PMA) as well as upon transfection w ith a EJ/ras encoding plasmid, Conversely, it was downmodulated upon t ransfection with wild-type p53 but not with mutated p53, The regulator y sequences involved in the positive regulation of the gene were locat ed upon serial deletion experiments.