Identification of Zfp393, a germ cell-specific gene encoding a novel zinc finger protein.

Department of Pathology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.

Using the digital differential display program of the National Center for Biotechnology Information, we identified a contig of expression sequence tags (ESTs) which were unique to ovary, testis, and egg libraries. The full-length cDNA of this transcript was deduced and further confirmed by reverse transcriptase polymerase chain reaction (RT-PCR). The cDNA encodes a novel protein of 341 amino acids with a nuclear localization signal. The carboxyl-terminus of the protein contains three C2H2 zinc fingers, and the NH(2)-terminus is proline and serine-rich. Based on the conserved zinc finger motifs, we have termed this novel protein as zinc finger protein 393 (ZFP393). Northern blot and RT-PCR analyses revealed that Zfp393 mRNA was exclusively expressed in testis and ovary. The expression sites were further localized by in situ hybridization to step 3-8 spermatids in testis and growing oocytes in ovary. The Zfp393 gene consists of three exons spanning approximately 8 kb on the distal part of mouse chromosome 4. The carboxyl-terminal zinc finger region is highly homologous to several zinc finger-containing proteins, but no proteins were found to share sequence similarity with the NH(2)-terminal region of ZFP393. Genomic database mining and Southern blot analysis indicate that Zfp393 is a single copy gene. We hypothesize that ZFP393 functions as a germ cell-specific transcription factor that plays important roles in spermatid differentiation and oocyte development.

PMID: 12351194 [PubMed - indexed for MEDLINE]