title: Differential transcription of exon 1 of the human c-fms gene in placental trophoblasts and monocytes.
abstract: Structural analysis of the 5' end of the human c-fms gene revealed that a large intron of about 25 kilobases separates an upstream noncoding exon (exon 1) from the signal peptide-containing exon (exon 2). Northern (RNA) blot analysis, S1 nuclease mapping, and primer extensions showed that exon 1 is transcribed in placenta but not in cells of the monocytic lineage. This is due to the differential usage of promoters, separated by approximately 25 kilobases, in a cell-specific manner. One major c-fms transcript was observed in U-937 cells, whereas multiple initiation sites for transcription appeared to be utilized in placental cells. Nucleotide sequence comparisons showed that the 3' end of the human platelet-derived growth factor receptor gene lies approximately 350 base pairs upstream of the major initiation sites for c-fms transcription in placental trophoblasts.
authors.affiliation: Molecular Biology and Virology Laboratory, Salk Institute, San Diego, California 92138.
authors.forename: J
authors.initials: J
authors.lastname: Visvader
authors.forename: I M
authors.initials: IM
authors.lastname: Verma
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D004247:DNA / Q000235:genetics; D005091:Exons; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D008969:Molecular Sequence Data; D009000:Monocytes / Q000378:metabolism*; D011247:Pregnancy; D011518:Proto-Oncogene Proteins / Q000235:genetics; D011519:Proto-Oncogenes; D016186:Receptor, Macrophage Colony-Stimulating Factor; D014158:Transcription, Genetic; D014327:Trophoblasts / Q000378:metabolism*
chemical_list: D011518:Proto-Oncogene Proteins; D004247:DNA; D016186:Receptor, Macrophage Colony-Stimulating Factor