Characterization of the Regulatory Domains of the Human Skn-1a/Epoc-1/Oct-11 POU Transcription Factor*
- From the ‡Dermatology Branch, NCI, National Institutes of Health, Bethesda, Maryland 20892-1908 and the§Cellular Biology and Metabolism Branch, NICHD, National Institutes of Health, Bethesda, Maryland 20892-5430
Abstract
The Skn-1a POU transcription factor is primarily expressed in keratinocytes of murine embryonic and adult epidermis. Although some POU factors expressed in a tissue-specific manner are important for normal differentiation, the biological function of Skn-1a remains unknown. Previous in vitro studies indicate that Skn-1a has the ability to transactivate markers of keratinocyte differentiation. In this study, we have characterized Skn-1a’s transactivation domain(s) and engineered a dominant negative protein that lacked this transactivation domain. Deletional analysis of the human homologue of Skn-1a with three target promoters revealed the presence of two functional domains: a primary C-terminal transactivation domain and a combined N-terminal inhibitory domain and transactivation domain. Skn-1a lacking the C-terminal region completely lost transactivation ability, irrespective of the promoter tested, and was able to block transactivation by normal Skn-1a in competition assays. Compared with full-length, Skn-1a lacking the N-terminal region demonstrated either increased transactivation (bovine cytokeratin 6 promoter), comparable transactivation (human papillomavirus type 1a long control region), or loss of transactivation (human papillomavirus type 18 long control region). The identification of a primary C-terminal transactivation domain enabled us to generate a dominant negative Skn-1a factor, which will be useful in the quest for a better understanding of this keratinocyte-specific gene regulator.
Footnotes
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↵* The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
The nucleotide sequence(s) reported in this paper has been submitted to the GenBank™/EMBL Data Bank with accession number(s) .
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↵¶ To whom correspondence should be addressed: Dermatology Branch, NCI, NIH, Bldg. 10, Rm. 12N238, 10 Center Dr., MSC 1908, Bethesda, MD 20892-1908. Tel.: 301-496-9002; Fax: 301-496-5370; E-mail: jonvogel@box-j.nih.gov.
- Abbreviations:
- K
-
cytokeratin
- CAT
-
chloramphenicol acetyltransferase
- HPV
-
human papillomavirus
- LCR
-
long control region
- ORF
-
open reading frame
- SPRR
-
small proline-rich protein
- TFs
-
transcription factors
- UTR
-
untranslated region
- RT-PCR
-
reverse transcription-polymerase chain reaction
- bp
-
base pair(s)
- kb
-
kilobase(s) or kilobase pair(s)
- FISH
-
fluorescent in situ hybridization
- EMSA
-
electromobility shift assay
- DAPI
-
4′,6′-diamidino-2-phenylindole
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- Received December 31, 1998.
- Revision received May 19, 1999.
- The American Society for Biochemistry and Molecular Biology, Inc.
