Identification of zinc finger mRNAs using domain-specific differential display

An oligonucleotide primer specific for a conserved amino acid region of the Cys2/His2 zinc finger proteins was used in conjunction with mRNA differential display to amplify related mRNAs from a human ovarian cancer cell line. Six of the 12 cDNAs analyzed from the differential display polyacrylamide gel exhibited zinc finger homology at the nucleotide and predicted amino acid sequence level. None of these cDNA fragments, however, shared complete homology with genes encoding any known zinc finger proteins. All 6 cDNA fragments with zinc finger homology had a poly-A tail and 3 of these fragments contained a putative polyadenylation signal. Northern blot analysis was performed using radiolabeled probes prepared from the 12 cDNA fragments. Two of the 6 cDNA fragments with zinc finger homology hybridized to 3.6- and 6.0-kb mRNAs. In addition, 2 of the fragments which did not contain significant homology to zinc finger or any other known sequences hybridized to 4.1- and 5.8-kb mRNAs. These results suggest that domain-specific differential display may be a useful approach for the identification of novel gene family members as well as for the analysis of changes in gene expression of family members between related cell lines or tissue samples.