title: Tissue-specific expression of c-Ha-ras in premalignant gastrointestinal mucosae.
abstract: The molecular mechanisms underlying premalignant gastrointestinal diseases, such as ulcerative colitis and Barrett's esophagus, remain unknown. For this reason, the expression of the protooncogene c-Ha-ras was studied in ulcerative colitis and Barrett's esophagus. Total cellular RNA was extracted from different regions of the gastrointestinal tract in these two diseases. Expression of c-Ha-ras was greater in proximal than in distal colon and undetectable in Barrett's esophagus. These regional differences in expression were not seen with the control gene beta-actin or with the protooncogenes c-myc and p53. In order to evaluate structural factors contributing to expression, amplification and methylation of c-Ha-ras DNA were studied in these tissues by Southern and slot blotting. No amplification of c-Ha-ras or six other protooncogenes was detected. These data suggest tissue-specific regulation of c-Ha-ras expression in the gastrointestinal tract in certain premalignant disease states.
authors.affiliation: Department of Medicine, University of Maryland, Baltimore.
authors.forename: S J
authors.initials: SJ
authors.lastname: Meltzer
authors.forename: D
authors.initials: D
authors.lastname: Zhou
authors.forename: W M
authors.initials: WM
authors.lastname: Weinstein
mesh_terms: D011125:Adenomatous Polyposis Coli / Q000235:genetics*; D001471:Barrett Esophagus / Q000235:genetics*; D003093:Colitis, Ulcerative / Q000235:genetics*; D003106:Colon / Q000502:physiology; D005784:Gene Amplification; D006801:Humans; D007413:Intestinal Mucosa / Q000473:pathology / Q000502:physiology*; D008745:Methylation; D015689:Oncogene Protein p21(ras) / Q000235:genetics*; D015513:Oncogene Proteins / Q000235:genetics; D010750:Phosphoproteins / Q000235:genetics; D011230:Precancerous Conditions / Q000235:genetics; D011518:Proto-Oncogene Proteins / Q000235:genetics; D016271:Proto-Oncogene Proteins c-myc; D011519:Proto-Oncogenes; D016159:Tumor Suppressor Protein p53
chemical_list: D015513:Oncogene Proteins; D010750:Phosphoproteins; D011518:Proto-Oncogene Proteins; D016271:Proto-Oncogene Proteins c-myc; D016159:Tumor Suppressor Protein p53; D015689:Oncogene Protein p21(ras)