DNA bending induced by specific interaction of decamer binding proteins with immunoglobulin gene control sequences.
In order to investigate the properties of specific DNA-binding proteins involved in tissue-specific regulation of immunoglobulin genes, we have analyzed the interaction of nuclear proteins from mouse B-cell hybridomas with promoter and enhancer sequences of a mouse immunoglobulin heavy chain gene. Visualization of specific complexes has shown that protein binding induces a sharp bend at the position of the conserved decamer sequence. After fractionation of nuclear extracts, several sequence-specific DNA binding proteins could be distinguished by UV crosslinking to radioactive synthetic oligonucleotides. Decamer binding factor I (DBF-I) a protein of 100-105 kDa and DBF-II, a family of proteins of 25-35 kDa were purified on specific DNA-affinity columns. Both proteins bend the DNA at the dc sequence as shown by electron microscopy and by gel retardation. These data suggest that one possible function of sequence-specific regulatory proteins may be to locally change the DNA topology, thereby facilitating the interaction of additional transcription factors with the primary complex.
Brack
C
C
Biozentrum, Department of Cell Biology, Basel, Switzerland.
Martin
G
G
Giller
T
T
Brunner
L
L
D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D004247:DNA / Q000378:metabolism* / Q000648:ultrastructure; D004268:DNA-Binding Proteins / Q000302:isolation & purification / Q000378:metabolism*; D004742:Enhancer Elements, Genetic; D005803:Genes, Immunoglobulin / Q000235:genetics*; D007143:Immunoglobulin Heavy Chains / Q000235:genetics; D051379:Mice; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D011401:Promoter Regions, Genetic; D012045:Regulatory Sequences, Nucleic Acid
D004268:DNA-Binding Proteins; D007143:Immunoglobulin Heavy Chains; D004247:DNA