We report the identification and characterization of the gene encoding the eighth and final human ribonuclease (RNase) of the highly diversified RNase A superfamily. The RNase 8 gene is linked to seven other RNase A superfamily genes on chromosome 14. It is expressed prominently in the placenta, but is not detected in any other tissues examined. Phylogenetic analysis suggests that RNase 7 is th...

Onconase (ONC) and bovine seminal ribonuclease (BS-RNase) are homologs of bovine pancreatic ribonuclease (RNase A). Unlike RNase A, ONC and BS-RNase can evade the cytosolic ribonuclease inhibitor protein and are potent cytotoxins. Here, the endogenous cytotoxic activities of ONC and BS-RNase are compared in a wide variety of assays. Injections of ONC into one or both testes of mice and rats evo...

Rana catesbeiana ribonuclease (RC-RNase) is a pyrimidine-guanine sequence-specific ribonuclease found in R. catesbeiana (bullfrog) oocytes. It possesses both ribonuclease activity and cytotoxicity against tumor cells. We report here for the first time the cloning of RC-RNase cDNA from liver rather than from oocytes where RC-RNase is stored. An internal fragment of cDNA was obtained by reverse t...

Mammalian RNase H1 has been implicated in mitochondrial DNA replication and RNA processing and is required for embryonic development. We identified the mitochondrial protein P32 that binds specifically to human RNase H1, but not human RNase H2. P32 binds human RNase H1 via the hybrid-binding domain of the enzyme at an approximately 1∶1 ratio. P32 enhanced the cleavage activity of RNase H1 by re...

RNase A (bovine pancreatic RNase) is the founding member an extensive family of divergent proteins that share specific elements of sequence homology, a unique disulfide-bonded tertiary structure, and the ability to hydrolyze polymeric RNA. Among the more intriguing and perhaps counterintuitive findings, at the current state of the art, the connection between RNase activity and characterized hos...

Rana catesbeiana ribonuclease (RC-RNase) is a pyrimidine-guanine sequence-specific ribonuclease found in R. catesbeiana (bullfrog) oocytes. It possesses both ribonuclease activity and cytotoxicity against tumor cells. We report here for the first time the cloning of RC-RNase cDNA from liver rather than from oocytes where RC-RNase is stored. An internal fragment of cDNA was obtained by reverse t...

Aeropyrum pernix contains one homolog of ribonuclease H (RNase H), A. pernix RNase HII (Ape-RNase HII). Activity characterization showed that Ape-RNase HII exhibited the highest activity in the presence of 5 mM Mn(2+), 1 mM Co(2+), or 10 mM Mg(2+), respectively; however, its cleavage efficiencies at different cleavage sites for Mn(2+) and Mg(2+) were different. Ape-RNase HII cleaved 12-bp RNA/D...

The RNase II superfamily is a ubiquitous family of exoribonucleases that are essential for RNA metabolism. RNase II and RNase R degrade RNA in the 3'-->5' direction in a processive and sequence-independent manner. However, although RNase R is capable of degrading highly structured RNAs, the RNase II activity is impaired by the presence of secondary structures. RNase II and RNase R share structu...

The ribonuclease P (RNase P) in the hyperthermophilic archaeon Pyrococcus horikoshii comprises RNA (PhopRNA) and five proteins. We analyzed the RNA binding mode of the protein, using a pair of complementary fluorescence-labeled oligoribonucleotides. Fluorescence resonance energy transfer (FRET)-based assays suggested that the RNase P proteins assist PhopRNA in attaining a functionally active co...

The regulation of ppp(A2'p)nA-(2-5A)-dependent RNase (RNase L or RNase F) was investigated in NIH 3T3, clone 1 cells using 2-5A-binding and nuclease activity assays. Minimal levels of 2-5A-dependent RNase were detected in actively dividing clone 1 cells; these levels were independently induced by growth arrest or interferon treatment. Accordingly, levels of the RNase were enhanced during growth...