TUMOR-SUPPRESSOR ACTIVITY OF H19 RNA

Loss of heterozygosity in certain human embryonal tumours implicates a tumour-suppressor gene at chromosome 11p15.5 and selective loss of ma ternal alleles suggests that this gene is paternally imprinted1-4. The human H19 gene maps to 11p15.5, is expressed in differentiating fetal cells5-11 and is paternally imprinted12-16. We report here that two e mbryonal tumour cell lines, RD and G401, showed growth retardation and morphological changes when transfected with an H19 expression constru ct. More importantly, clonogenicity in soft agar and tumorigenicity in nude mice were abrogated in the G401-H19 transfectants. In addition t o demonstrating its tumour-suppressor potential, this transfection sys tem should help structural and functional studies of the enigmatic H19 gene.