Chemical reverse transformation of CHO-K1 cells induces changes in expression of a candidate tumour suppressor and of a gene not previously characterised as transformation related.
Chemical reverse transformation of CHO-K1 and other cells is a well-established phenomenon, in which oncogenically transformed cells re-acquire fibroblastoid morphology, contact inhibition and anchorage-dependent growth, in response to cyclic AMP and other agents. A limited number of changes in gene transcription and enzyme activity have been demonstrated to coincide with these morphological and physiological changes. We have used a partial differential display to identify four genes that are transcriptionally modulated in reverse transformation. One of these, encoding ribosomal protein S18, is transcriptionally suppressed, probably as a result of the detransforming process. Three others are transcriptionally activated. One has homology to NADH-ubiquinone oxidoreductase chain 4 protein, and is also probably changed as a result of the detransforming process. Another is homologous to a human sequence which encodes a 27 kDa protein, p27(BBP/eIF6), that is involved in the biogenesis of 60S ribosomal subunit, and in cell lines of epithelial origin binds to beta integrin. This has not previously been described as transformation-related, and could have a causative role in reverse transformation. The third has homology, with transcriptional or processing variations, to a human genomic sequence, a positional candidate for a tumour suppressor gene, encoding the Krit1 protein which interacts with the Ras-family GTPase Krev-1.
Bachrati
C Z
CZ
Institute of Genetics, Biological Research Centre of Hungarian Academy of Sciences, Szeged. csanad@rosi.szbk.u-szeged.hu
Downes
C S
CS
Raskó
I
I
D000818:Animals; D015152:Blotting, Northern; D016466:CHO Cells / Q000378:metabolism; D002897:Chromosomes, Human, Pair 7; D006224:Cricetinae; D018076:DNA, Complementary / Q000032:analysis; D020224:Expressed Sequence Tags; D005786:Gene Expression Regulation; D016147:Genes, Tumor Suppressor / Q000235:genetics*; D006801:Humans; D008957:Models, Genetic; D008969:Molecular Sequence Data; D012313:RNA / Q000032:analysis; D017386:Sequence Homology, Amino Acid; D014170:Transformation, Genetic
D018076:DNA, Complementary; D012313:RNA