Inhibitory effect of oryzacystatins and a truncation mutant on the replication of poliovirus in infected Vero cells

Abstract

Poliovirus, a picornavirus family member, requires the processing of its poly-protein by its own cystein¢ protcinasc for replication. Oryzacystatin-I and oryza~statin-lI, proteinaceous cysteine proteinase inhibitors (cystatins) of rice seed orisin, were found to inhibit the replication of poliovirus effectively in infected Veto cells in vitro. Truncated oryzacystatin-I, which lacks the NH.,-terminal 25 amino acid residues of the intact protein, is an even more effective inhibitor, eliciting its effect at concentrations of less than 0.25 nmol/ml. The low molecular weight cysteine proteinase inhibitors, E-64, E-64C and loxistatin, showed no anti-viral effect at any concentration investigated.

Proteinase inhibitors and their function in plants: A review

“…Cystatins may also play a role in plant defense from viral diseases. This is due to the involvement of cysteine proteinases in processing of viral proteins [344]. For example, transgenic tobacco plants expressing the gene of oryzacystatin are highly resistant to tobacco etch virus and potato Y virus [345].…”

Role of inhibitors of proteolytic enzymes in plant defense against phytopathogenic microorganisms

“…In this respect, cysteine proteinases become an attractive target for the development of efficient control means of plant and ani mal viral diseases [62]. Initial experiments have revealed that plant inhibitors (oryzacystatins I and II) are able to suppress replication of animal viruses belonging to the picornaviruses family [63]. Later, transgenic tobacco plants containing the oryzacystatin I gene were obtained.…”

Decreased metastatic spread in mice homozygous for a null allele of the cystatin C protease inhibitor gene

“…3 4 Indeed, cystatin C is present in virtually all mammalian tissues, although the inhibitor is found at particularly high concentrations in the cerebrospinal fluid of the central nervous system (CNS). 5 In vitro experiments have indicated that cystatins have a broad spectrum of biological roles, in processes ranging from bone resorption, 6 7 processing of certain prohormones, 8 modulation of neutrophil chemotactic activity and inflammation, 9 10 and resistance to a range of bacterial 11 and viral [12][13][14] infections. Cysteine proteases of certain parasitic protozoa 15 16 could be another target for cystatin inhibition.…”