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 (MB P)-encoding gene (Mbp) in brain is regulated by arrays of cis-acting r egulatory elements positioned at the 5'-flanking region of the gene. T he proximal element between nucleotides - 14 to - 50, termed MB1, has previously been shown to have an important role in the cell-type-speci fic transcription of Mbp in cells derived from the central nervous sys tem (CNS). Here, we utilized band-shift and in vitro transcription ass ays 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 reg ulating transcription of the Mbp promoter. Results from the bandshift assays indicated that the bacterially produced MEF-2 recognizes specif ic nt in the MB1 motif, and its binding to these nt reduces the overal l transcriptional activity of Mbp in a cell-free extract.