title: Expression of the parathyroid hormone-related peptide gene in retinoic acid-induced differentiation: involvement of ETS and Sp1.
abstract: Differentiation of P19 embryonal carcinoma (EC) and embryonal stem (ES)-5 cells with retinoic acid (RA) induces expression of PTH-related peptide (PTHrP) mRNA. In this study we have characterized a region between nucleotide (nt) -88 and -58 relative to the transcription start site in the murine PTHrP gene that was involved in this expression. Sequence analysis identified two partially overlapping binding sites for the Ets family of transcription factors and an inverted Sp1-binding site. Two major specific bands were detected in a bandshift assay using an oligonucleotide spanning nt -88 and -58 as a probe and nuclear extracts from both undifferentiated and RA-differentiated P19 EC cells. The lower complex consisted of Ets-binding proteins as demonstrated by competition with consensus Ets-binding sites, while the upper complex contained Sp1-binding activity as demonstrated by competition with consensus Sp1-binding sites. The observed bandshift patterns using nuclear extracts of undifferentiated or RA-differentiated P19 cells were indistinguishable, suggesting that the differentiation-mediated expression was not caused by the induction of expression of new transcription factors. Mutations in either of the Ets-binding sites or the Sp1-binding site completely abolished RA-induced expression of PTHrP promoter reporter constructs, indicating that the RA effect was dependent on the simultaneous action of both Ets- and Sp1-like activities. Furthermore, these mutations also abolished promoter activity in cells that constitutively expressed PTHrP mRNA, suggesting a central role for the Ets and Sp1 families of transcription factors in the expression regulation of the mouse PTHrP gene.
authors.affiliation: Department of Endocrinology, Leiden University, The Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: Karperien
authors.forename: H
authors.initials: H
authors.lastname: Farih-Sips
authors.forename: C W
authors.initials: CW
authors.lastname: Löwik
authors.forename: S W
authors.initials: SW
authors.lastname: de Laat
authors.forename: J
authors.initials: J
authors.lastname: Boonstra
authors.forename: L H
authors.initials: LH
authors.lastname: Defize
mesh_terms: D000818:Animals; D001483:Base Sequence; D002454:Cell Differentiation / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D007641:Keratolytic Agents / Q000494:pharmacology*; D051379:Mice; D008969:Molecular Sequence Data; D044162:Parathyroid Hormone-Related Protein; D014176:Protein Biosynthesis; D011506:Proteins / Q000235:genetics*; D011518:Proto-Oncogene Proteins / Q000502:physiology*; D050783:Proto-Oncogene Proteins c-ets; D051381:Rats; D016415:Sequence Alignment; D015398:Signal Transduction; D016329:Sp1 Transcription Factor / Q000502:physiology*; D013234:Stem Cells / Q000502:physiology*; D014157:Transcription Factors / Q000502:physiology*; D014212:Tretinoin / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
chemical_list: D007641:Keratolytic Agents; C470121:PTHLH protein, human; D044162:Parathyroid Hormone-Related Protein; D011506:Proteins; D011518:Proto-Oncogene Proteins; D050783:Proto-Oncogene Proteins c-ets; D016329:Sp1 Transcription Factor; D014157:Transcription Factors; D014212:Tretinoin