Targeted Melting and Binding of a DNA Regulatory Element by a Transactivator of c-myc

摘要: Abstract A far upstream element (FUSE) of c-myc stimulates promoter activity when bound by a newly identified trans-acting protein, which is expressed in cycling cells. Since FUSE binding protein (FBP) binds only the noncoding strand (NCS) its regulatory sequence-specific manner, and not double-stranded (ds) DNA, formation protein•DNA complex vivo first requires unwinding DNA helix. In this report, we show evidence that FBP forces separation short stretches linear dsDNA. Because contained within region helical instability partially unwound negatively supercoiled it target for more extensive duplex FBP, exposes then selectively NCS cognate sequence. contrast, other single-stranded proteins (SSBs) do demonstrate targeting activity. The novel linkage regional dsDNA melting with cis-element transcriptional activator has broad implications regulation eukaryotic gene expression.