TRANSCRIPTIONAL REPRESSOR ZF5 IDENTIFIES A NEW CONSERVED DOMAIN IN ZINC-FINGER PROTEINS

We have cloned a cDNA encoding a new murine C2H2 zinc finger protein, ZF5. The 51.3 kD protein contains five GL1-Kruppel type zinc fingers a t the C-terminus. At its N-terminus, ZF5 has a 41 amino acid region wh ich was found to be homologous to the N-termini of several other zinc finger proteins. This region defines a new motif within zinc finger pr oteins which we have named the Zinc finger N-terminal (ZiN) domain.ZF5 binds to two sites in the c-myc promoter and to the -50 bp site of th e herpes simplex thymidine kinase promoter. ZF5 is a transcriptional r epressor and its repression domain is located N-terminal to the zinc f inger domains. A single 4 kb ZF5 mRNA is expressed widely.