Transcriptional repressor of the myelin basic protein gene (MBP). Binds to the proximal MB1 element 5'-TTGTCC-3' of the MBP promoter. Its binding to MB1 and function are inhibited by PURA (By similarity). . This is the function of Ensembl gene identifier ENSG00000104177 (MYEF2, myelin expression factor 2).