Characterization of a 1.8-kb DNA segment located upstream from the human Ha-ras protooncogene and possibly regulating its function.
We have cloned a 1.8-kb segment of DNA just adjacent to the 5' end of the 6.4-kb BamHI fragment which contains the Ha-ras oncogene (ras1; GenBank notation HUMRASH). Electrophoretic mobility shift assays (EMSA) indicate the presence of multiple nuclear protein-binding sites within the 1.8-kb segment. At least three putative regulatory protein-binding sites have been identified in a 206-bp subfragment by DNase I footprint analysis. Within the subfragment containing the DNase-protected regions, there is also a segment containing a number of consensus sequences for DNA-binding proteins and two sub-sequences that exhibit strong sequence homology to at least two previously characterized enhancers. These data suggest that a novel set of regulatory elements may lie as far as 2 kb upstream from the normal Ha-ras transcription start points.
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Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.
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Steinberg
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D000595:Amino Acid Sequence; D001483:Base Sequence; D002461:Cell Line, Transformed; D003001:Cloning, Molecular; D011905:Genes, ras / Q000235:genetics*; D015698:Genomic Library; D006367:HeLa Cells; D006801:Humans; D015603:Keratinocytes / Q000378:metabolism; D008969:Molecular Sequence Data; D017421:Sequence Analysis; D014158:Transcription, Genetic