Multiple domains of the RNA polymerase I activator hUBF interact with the TATA-binding protein complex hSL1 to mediate transcription
| Autor: | H M Jantzen, A M Chow, D S King, R Tjian |
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| Rok vydání: | 1992 |
| Předmět: |
Transcription
Genetic Macromolecular Substances TATA box Molecular Sequence Data RNA polymerase II Hybrid Cells Xenopus laevis RNA Polymerase I Genetics RNA polymerase I Animals Humans Promoter Regions Genetic Base Sequence biology General transcription factor TATA-Box Binding Protein DNA TATA Box Molecular biology Cell biology DNA-Binding Proteins Enzyme Activation Pol1 Transcription Initiation Complex Proteins RNA Ribosomal Protein Biosynthesis biology.protein Transcription factor II D TATA-binding protein Plasmids Protein Binding Transcription Factors Developmental Biology |
| Zdroj: | Genes & Development. 6:1950-1963 |
| ISSN: | 1549-5477 0890-9369 |
| Popis: | Recent evidence suggests that transcription initiation by all three eukaryotic RNA polymerases involves a complex of the TATA-binding protein (TBP) and multiple TBP-associated factors (TAFs). Here, we map the functional domains of the nucleolar HMG box protein hUBF, which binds to the human rRNA promoter and stimulates transcription by RNA polymerase I through cooperative interactions with a distinct TBP-TAF complex, hSL1. DNase I footprint analysis of mutant hUBF proteins and of a synthetic peptide of 84 amino acids reveals that HMG box 1 is necessary and sufficient for DNA sequence specificity, whereas other HMG boxes and the amino terminus modulate the binding efficiency. hUBF contains multiple activation domains that include the acidic carboxyl terminus and three HMG boxes. HMG boxes 3 and 4 and the acidic tail contribute significantly to an extended footprinting pattern in the presence of hSL1, suggestive of specific protein-protein interactions. Moreover, the inability of xUBF from Xenopus laevis to form an initiation complex with hSL1 can be overcome by hybrid proteins containing human HMG box 4 and the acidic carboxyl terminus. These results strongly suggest an important role of transcription activation domains of hUBF in mediating interactions with the TBP-TAF complex hSL1. |
| Databáze: | OpenAIRE |
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