Identification of SNAPc subunit domains that interact with specific nucleotide positions in the U1 and U6 gene promoters.
Mol Cell Biol
; 30(10): 2411-23, 2010 May.
Article
em En
| MEDLINE
| ID: mdl-20212087
ABSTRACT
The small nuclear RNA (snRNA)-activating protein complex (SNAPc) is essential for transcription of genes coding for the snRNAs (U1, U2, etc.). In Drosophila melanogaster, the heterotrimeric DmSNAPc recognizes a 21-bp DNA sequence, the proximal sequence element A (PSEA), located approximately 40 to 60 bp upstream of the transcription start site. Upon binding the PSEA, DmSNAPc establishes RNA polymerase II preinitiation complexes on U1 to U5 promoters but RNA polymerase III preinitiation complexes on U6 promoters. Minor differences in nucleotide sequence of the U1 and U6 PSEAs determine RNA polymerase specificity; moreover, DmSNAPc adopts different conformations on these different PSEAs. We have proposed that such conformational differences in DmSNAPc play a key role in determining the different polymerase specificities of the U1 and U6 promoters. To better understand the structure of DmSNAPc-PSEA complexes, we have developed a novel protocol that combines site-specific protein-DNA photo-cross-linking with site-specific chemical cleavage of the protein. This protocol has allowed us to map regions within each of the three DmSNAPc subunits that contact specific nucleotide positions within the U1 and U6 PSEAs. These data help to establish the orientation of each DmSNAPc subunit on the DNA and have revealed cases in which different domains of the subunits differentially contact the U1 versus U6 PSEAs.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
RNA Nuclear Pequeno
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Regiões Promotoras Genéticas
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Subunidades Proteicas
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Proteínas de Drosophila
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Proteínas de Ligação a DNA
Tipo de estudo:
Diagnostic_studies
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Prognostic_studies
Limite:
Animals
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Humans
Idioma:
En
Revista:
Mol Cell Biol
Ano de publicação:
2010
Tipo de documento:
Article