Purification and Characterization of the Stage-Specific Embryonic Enhancer-Binding Protein SSAP-1
| Autor: | Geoffrey J. Childs, Daniel J. DeAngelo, Jeffery Defalco |
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| Rok vydání: | 1993 |
| Předmět: |
Chloramphenicol O-Acetyltransferase
Time Factors Microinjections Transcription Genetic Protein Conformation Zygote Molecular Sequence Data Oligonucleotides Biology Binding Competitive Histones Histone H1 Antibody Specificity Transcription (biology) Enhancer binding Gene expression Animals Enhancer Gene Molecular Biology Cell Nucleus Regulation of gene expression Base Sequence Chromosome Mapping Cell Biology Blastula Molecular biology Recombinant Proteins Cell biology DNA-Binding Proteins Enhancer Elements Genetic Sea Urchins Research Article |
| Zdroj: | Molecular and Cellular Biology. 13:1746-1758 |
| ISSN: | 1098-5549 |
| Popis: | We have demonstrated that a highly conserved segment of DNA between positions -288 and -317 (upstream sequence element IV [USE IV]) is largely responsible for the transcriptional activation of the sea urchin H1-beta histone gene during the blastula stage of embryogenesis. This sequence is capable of acting as an embryonic enhancer element, activating target genes in a stage-specific manner. Nuclear extracts prepared from developmentally-staged organisms before and after the gene is activated all contain a factor which specifically binds to the enhancer. We have purified a 43-kDa polypeptide which binds to and footprints the USE IV enhancer element. We refer to this protein as stage-specific activator protein 1 (SSAP-1). Early in development before the enhancer is active, SSAP appears as a 43-kDa monomer, but it undergoes a change in its molecular weight beginning at about 12 h postfertilization (early blastula) which precisely parallels the increase in H1-beta gene expression. Modified SSAP has an apparent molecular mass of approximately 90 to 100 kDa and contains at least one 43-kDa SSAP polypeptide. Thus, it is the disappearance of the 43-kDa species and the appearance of the 90- to 100-kDa species which coincide with the H1-beta gene activation. The correlation between the change in molecular weight of SSAP and the stage-specific activation of H1-beta gene expression strongly suggests that this higher-molecular-weight form of SSAP is directly responsible for the blastula stage-specific transcriptional activation of the late H1 gene. |
| Databáze: | OpenAIRE |
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