Identification of a Novel Human Zinc Finger Protein Gene ZNF474 by Digital Differential Display

Abstract : This study was designed to identify a novel testis overexpressed gene related to spermatogenesis by a new strategy of digital differential display (DDD). Based on the generation of expressed sequenced tags (ESTs), comparing the testis libraries with other tissue or cell line libraries by the DDD program, we identified a new contig of the ESTs which were derived from testis libraries and represented a novel gene. A full-length cDNA sequence of the new gene named ZNF474 (GeneBank accession number AY461732) by the HUGO Gene Nomenclature Committee in human testis was identified. ZNF474 was 1972 bp in length, located in chromosome 5q23.2. The sequence of the opening reading frame was 377-1471 bp, as was confirmed by RT-PCR and sequencing. The cDNA encodes a novel protein of 364 amino acids protein that was 66% identical to a mouse homologue. Northern blot analyses revealed that ZNF474 mRNA was exclusively expressed in testis and ovary and has one transcript. In situ hybridization revealed that ZNF474 high expressed in adult testis and seminoma. The brown granules of hybridization signal were found in spermatocyte, spermatids and spermatozoa, no expression in sertoli's cells and leydig's cells. We hypothesize that ZNF474 functions as a germ cell-specific transcription factor that plays important roles in spermatid differentiation and oocyte development.