PDZ domain-mediated dimerization and homeodomain-directed specificity are required for high-affinity DNA binding by SATB1
| Autor: | Prabhat Kumar Purbey, Sunita Singh, Debashis Mitra, Sameet Mehta, K. N. Ganesh, Praveen Kumar, Sanjeev Galande |
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| Rok vydání: | 2008 |
| Předmět: |
Models
Molecular HMG-box Genes Immunoglobulin Heavy Chain PDZ Domains Repressor Biology Cell Line 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine Consensus Sequence Genetics Consensus sequence Humans Cloning Molecular Binding site Molecular Biology Transcription factor 030304 developmental biology Palindromic sequence Homeodomain Proteins 0303 health sciences Binding Sites Base Sequence SELEX Aptamer Technique DNA Matrix Attachment Region Binding Proteins Matrix Attachment Regions AT Rich Sequence Molecular biology Protein Structure Tertiary Cell biology Repressor Proteins DNA binding site chemistry 030220 oncology & carcinogenesis Dimerization Protein Binding |
| Zdroj: | Nucleic Acids Research |
| ISSN: | 1362-4962 0305-1048 |
| DOI: | 10.1093/nar/gkm1151 |
| Popis: | To better understand DNA recognition and transcription activity by SATB1, the T-lineage-enriched chromatin organizer and transcription factor, we have determined its optimal DNA-binding sequence by random oligonucleotide selection. The consensus SATB1-binding sequence (CSBS) comprises a palindromic sequence in which two identical AT-rich half-sites are arranged as inverted repeats flanking a central cytosine or guanine. Strikingly, the CSBS half-site is identical to the conserved element 'TAATA' bound by the known homeodomains (HDs). Furthermore, we show that the high-affinity binding of SATB1 to DNA is dimerization-dependent and the HD also binds in similar fashion. Binding studies using HD-lacking SATB1 and binding target with increased spacer between the two half-sites led us to propose a model for SATB1-DNA complex in which the HDs bind in an antiparallel fashion to the palindromic consensus element via minor groove, bridged by the PDZ-like dimerization domain. CSBS-driven in vivo reporter analysis indicated that SATB1 acts as a repressor upon binding to the CSBS and most of its derivatives and the extent of repression is proportional to SATB1's binding affinity to these sequences. These studies provide mechanistic insights into the mode of DNA binding and its effect on the regulation of transcription by SATB1. |
| Databáze: | OpenAIRE |
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