title: Identification of genes that exhibit increased expression after flat reversion of NIH/3T3 cells transformed by human activated Ha-ras oncogene.
abstract: By differential hybridization, we have isolated 14 cDNA clones corresponding to genes that are more highly expressed in the flat revertant cell line R1 than in the parental human Ha-ras oncogene-transformed NIH/3T3 cell line (EJ-NIH/3T3). From cross-hybridization experiments, we determined that 5 sequence families accounted for the 14 clones. DNA sequencing revealed that four out of five selected cDNA clones represented mitochondrial genes (cytochrome b, cytochrome c oxidase subunit II, NADH dehydrogenase subunits 1 and 4, respectively), whereas one cDNA clone was homologous to the alpha 2 (type I collagen gene. Although a Southern blot analysis of the studied cell lines showed similar copy numbers of mitochondrial genomes, the transcript levels of the mitochondrial genes were high in R1, intermediate in NIH/3T3 and low in EJ-NIH/3T3 and partially revertant R2 cell lines. alpha 2 (type I) collagen mRNA levels were high in R1 and NIH/3T3, intermediate in R2 and low in EJ-NIH/3T3 cells. These results suggest that a complex alteration of the expression of mitochondrial and extracellular matrix components may be closely associated with the flat reversion of the transformed cells.
authors.affiliation: Laboratory of Molecular Genetics, Cancer Institute, Hokkaido University School of Medicine, Sapporo, Japan.
authors.forename: L
authors.initials: L
authors.lastname: Müllauer
authors.forename: H
authors.initials: H
authors.lastname: Suzuki
authors.forename: H
authors.initials: H
authors.lastname: Fujita
authors.forename: M
authors.initials: M
authors.lastname: Katabami
authors.forename: N
authors.initials: N
authors.lastname: Kuzumaki
mesh_terms: D000818:Animals; D015152:Blotting, Northern; D015139:Blotting, Southern; D002471:Cell Transformation, Neoplastic / Q000235:genetics*; D005260:Female; D015870:Gene Expression / Q000502:physiology*; D015723:Gene Library; D011905:Genes, ras / Q000235:genetics*; D006801:Humans; D008297:Male; D009693:Nucleic Acid Hybridization