Regulation of mouse myelin basic protein gene transcription by a sequence-specific single-stranded DNA-binding protein in vitro.

Cell- and stage-specific transcription of the myelin basic protein (MBP)-encoding gene (Mbp) in brain is regulated by arrays of cis-acting regulatory elements positioned at the 5'-flanking region of the gene. The proximal element between nucleotides -14 to -50, termed MB1, has previously been shown to have an important role in the cell-type-specific transcription of Mbp in cells derived from the central nervous system (CNS). Here, we utilized band-shift and in vitro transcription assays to examine the ability of MEF-2, an expression factor encoded by a cDNA isolated from mouse brain, in binding to the MB1 element and regulating transcription of the Mbp promoter. Results from the band-shift assays indicated that the bacterially produced MEF-2 recognizes specific nt in the MB1 motif, and its binding to these nt reduces the overall transcriptional activity of Mbp in a cell-free extract.