Identification of Zinc Finger Genes that are Differentially Expressed upon Apoptosis of Ramos B Cells

ABSTRACT

Typical programmed cell death requires de novo macromolecular synthesis and shares common morphological changes referred to as apoptosis. To elucidate the molecular mechanism of apoptosis, we isolated 13 cDNA clones of zinc finger genes that are differentially expressed in calcium ionophore-induced apoptosis of Ramos human B cell by 'targeted RNA fingerprinting' protocol (Stone & Wharton, 1993). According to DNA sequence analysis of the 13 cDNA clones, three clones are identical with ZNF7, ZNF143 and MTB-Zf, respectively, and 8 out of the other 10 clones showed partial homology to known zinc finger genes. Differential expression was confirmed in the three known zinc finger genes by ribonuclease protection assay. ZNF7 and ZNF143 are up-regulated after induction of apoptosis, and, in contrast, MTB-Zf is down-regulated. According to the previous reports on these three genes, all of the three genes have been suspected to be tumor suppressor genes, but their functions have not been identified yet. Taken together, our results suggest that many of the novel and known zinc finger genes might play important roles in regulation of apoptosis and that these findings also provide clues as to the functions of the three putative tumor suppressor genes, ZNF7, ZNF143 and MTB-Zf in terms of apoptosis. In addition, the isolation of zinc finger genes by targeted RNA fingerprinting could be a straightforward approach for the identification of novel candidate genes associated with apoptosis.