Involvement of a single‐stranded DNA binding protein, ssCRE‐BP/Purα, in morphine dependence

Abstract
We have purified a nuclear protein from mouse cerebella that binds to single-stranded oligo-DNA of cAMP response element and is modulated by morphine treatment. Isolation of the cDNA clone showed that the nuclear protein (ssCRE-BP) was identical to Purα, a DNA binding protein for single-stranded purine-rich sequences that was originally isolated as a replication factor. ssCRE-BP/Purα and mRNA were abundant in the brain. The levels of ssCRE-BP/Purα and the transcript were not changed by chronic morphine treatment, however, the levels of an activator of ssCRE-BP/Purα, which is necessary for the DNA binding, may be modulated by the treatment.