THE LEU-ENKEPHALIN-ENCODING SEQUENCE DNA-BINDING FACTOR (LEF) IS THE TRANSCRIPTION FACTOR YY1

The Leu-enkephalin-encoding sequence DNA-binding factor (LEF) with hig h affinity for the Leu-enkephalin-encoding sequences in the prodynorph in and proenkephalin genes has earlier been identified. This factor is composed of three subunits of about 60, 70 (the major DNA-binding sub unit), and 95 KDa, respectively. Estimated molecular mass, sequence sp ecificity of DNA-binding, and supershift/inhibition with specific anti bodies in a band shift assay showed that the DNA-binding subunit of LE F is identical to the multifunctional transcription factor YY1. Howeve r, an antibody against the C-terminus of YY1 distinguished the YY1 com plexes with a Leu-enkephalin-encoding sequence and canonical YY1 bindi ng site oligonucleotides, suggesting different protein conformations i n complexes with these two DNA fragments. (C) 1997 Academic Press.