Interdependent transcription control elements regulate the expression of the SPRR2A gene during keratinocyte terminal differentiation.
Expression of the SPRR2A gene, a member of the small proline-rich family of cornified cell envelope precursor proteins, is strictly linked to keratinocyte terminal differentiation both in vivo and in vitro. In this study, we explored the molecular mechanisms underlying this regulation in transiently transfected primary keratinocytes induced to differentiate in vitro. Deletion mapping and site-directed mutagenesis of SPRR2A promoter-chloramphenicol acetyltransferase constructs indicate that four transcription control elements are essential and sufficient for promoter activity. These elements were further characterized by electrophoretic mobility shift and identified as (i) an inverted octamer doublet, bound by the POU domain factor Oct-11 (Skn-1a/i, Epoc-1), (ii) an interferon-stimulated response element recognized by interferon regulatory factors 1 and 2, (iii) an Ets binding site partially overlapping the interferon-stimulated response element, and (iv) a TG box recognized by the Sp1 family of zinc finger transcription factors. Destruction of a single terminal differentiation element is sufficient to completely abolish transcription from the SPRR2A promoter, indicating that these transcription control elements function in concert in an interdependent manner. Apparently, integration of signals transmitted by the above-mentioned transcription factors is necessary and sufficient to promote gene expression during keratinocyte terminal differentiation.
Fischer
D F
DF
Laboratory of Molecular Genetics, Leiden Institute of Chemistry, Leiden University, The Netherlands.
Gibbs
S
S
van De Putte
P
P
Backendorf
C
C
D001483:Base Sequence; D002118:Calcium / Q000494:pharmacology; D002454:Cell Differentiation; D002478:Cells, Cultured; D015500:Chloramphenicol O-Acetyltransferase / Q000096:biosynthesis; D055233:Cornified Envelope Proline-Rich Proteins; D004252:DNA Mutational Analysis; D004268:DNA-Binding Proteins / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D015603:Keratinocytes / Q000166:cytology* / Q000378:metabolism*; D007700:Kinetics; D008565:Membrane Proteins / Q000096:biosynthesis*; D009838:Oligodeoxyribonucleotides; D011401:Promoter Regions, Genetic; D011498:Protein Precursors / Q000096:biosynthesis*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D012867:Skin / Q000166:cytology; D016385:TATA Box; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic; D014162:Transfection; D016335:Zinc Fingers
D055233:Cornified Envelope Proline-Rich Proteins; D004268:DNA-Binding Proteins; D008565:Membrane Proteins; D009838:Oligodeoxyribonucleotides; D011498:Protein Precursors; D011993:Recombinant Fusion Proteins; C101744:SPRR2A protein, human; D014157:Transcription Factors; D015500:Chloramphenicol O-Acetyltransferase; D002118:Calcium