Cloning And Functional Analyses Of A Novel Human Zinc Finger Protein Gene ZNF641 And A Novel Human Homolog HSVOP Of Vesicle Proteins

Transcription factors play important roles in a variety of cellular functions, including cell growth, proliferation, apoptosis and intracellular signal transduction. Several large families of transcription factors have been identified, and in mammals, zinc finger proteins probably constitute the largest individual family. The zinc finger-containing transcription factor has been implicated as a critical regulator of multiple cardiac-expressed genes . With the aim of identifying the genes involved in human heart development and related to heart diseases, we have isolated and characterized a novel zinc-finger gene named ZNF641 from an early human embryo heart cDNA library, which is mapped to 12ql3.11. The cDNA sequence of gene ZNF641 consists of an open reading frame of 1317 bp, encoding a putative protein of 438 amino acid residues with a predicted molecular mass of 49. 5 kDa, which contains a KRAB box in N-teminal and 5 C₂H₂ zinc fingers in C-terminal. Northern blot analysis indicated that a 4. 9 kb transcript specific for ZNF641 was expressed extensively in the adult tissues. Among the 8 tissues tested at adult stage, the gene was strongly expressed in skeletal muscle, but showed a moderate expression in heart, pancreas and liver, a lower expression in placenta and noexpression in brain, lung and kidney. In addition, PEGFP-ZNF641 fusion mammalian expression protein were constructed and introduced into the COS-7 cells. Observation under the fluorescent microscopy showed that PEGFP-ZNF641 was located in nucleus as well as in cytoplasm. Reporter gene assays implied that ZNF641 is a transcriptional activator. Using fragment deletion analysis, it is shown that ZNF641 contains a transcriptional activation domain in its linker motif. Overexpression of ZNF641 in COS-7 cells activated the transcriptional activities of AP-1 and SRE, suggesting that ZNF641 may act as a transcriptional activator and a positive regulator in MAPK-mediated signaling pathways. Taken together, these results indicate that ZNF641 is a zinc finger transcription factor which may be involved in the development of multiple embryonic organs.In addition, we have isolated a novel human homolog of synaptic vesicles proteins named hSVOP from a human brain cDNA library. The full length cDNA of this gene is 3556 bp and it contains an open reading frame of 1646 nucleotides, coding for a protein 548 amino acids. Bioinformatics analysis indicates that it is mapped to chromosome 12q24. 12 and the protein contains 12 transmembrane regions. Northern blot analysis...