THE CENTROMERIC NUCLEOLAR CHROMATIN PROTEIN ZFP-37 MAY FUNCTION TO SPECIFY NEURONAL NUCLEAR DOMAINS/

Murine ZFP-37 is a member of the large family of C2H2 type zinc finger proteins, It is characterized by a truncated NH2-terminal Kruppel-ass ociated box and is thought to play a role in transcriptional regulatio n. During development Zfp-37 mRNA is most abundant in the developing c entral nervous system, and in the adult mouse expression is restricted largely to testis and brain, Here we show that at the protein level Z FP-37 is detected readily in neurons of the adult central nervous syst em but hardly in testis, In brain ZFP-37 is associated with nucleoli a nd appears to contact heterochromatin. Mouse and human ZFP-37 have a b asic histone H1-like linker domain, located between KRAB and zinc fing er regions, which binds double-stranded DNA. Thus we suggest that ZFP- 37 is a structural protein of the neuronal nucleus which plays a role in the maintenance of specialized chromatin domains.