Evolution of antiviral activity in the ribonuclease A gene superfamily: evidence for a specific interaction between eosinophil-derived neurotoxin (EDN/RNase 2) and respiratory syncytial virus.
We have demonstrated that the human eosinophil-derived neurotoxin (EDN, RNase 2), a rapidly evolving secretory protein derived from eosinophilic leukocytes, mediates the ribonucleolytic destruction of extracellular virions of the single-stranded RNA virus respiratory syncytial virus (RSV). While RNase activity is crucial to antiviral activity, it is clearly not sufficient, as our results suggest that EDN has unique structural features apart from RNase activity that are necessary to promote antiviral activity. We demonstrate here that the interaction between EDN and extracellular virions of RSV is both saturatable and specific. Increasing concentrations of the antivirally inactivated, ribonucleolytically inactivated point mutant form of recombinant human EDN, rhEDNdK38, inhibits rhEDN's antiviral activity, while increasing concentrations of the related RNase, recombinant human RNase k6, have no effect whatsoever. Interestingly, acquisition of antiviral activity parallels the evolutionary development of the primate EDN lineage, having emerged some time after the divergence of the Old World from the New World monkeys. Using this information, we created ribonucleolytically active chimeras of human and New World monkey orthologs of EDN and, by evaluating their antiviral activity, we have identified an N-terminal segment of human EDN that contains one or more of the sequence elements that mediate its specific interaction with RSV.
Domachowske
J B
JB
Department of Pediatrics, Division of Infectious Diseases, State University of New York Health Science Center at Syracuse, Syracuse, NY 13210, USA.
Bonville
C A
CA
Dyer
K D
KD
Rosenberg
H F
HF
D000595:Amino Acid Sequence; D000818:Animals; D000998:Antiviral Agents / Q000235:genetics / Q000494:pharmacology* / Q000502:physiology; D016645:Aotidae; D004722:Endoribonucleases / Q000235:genetics / Q000502:physiology*; D047208:Eosinophil-Derived Neurotoxin; D019143:Evolution, Molecular; D005110:Extracellular Space / Q000201:enzymology / Q000821:virology; D006801:Humans; D008252:Macaca fascicularis; D008969:Molecular Sequence Data; D011148:Pongo pygmaeus; D011506:Proteins / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000502:physiology; D018113:Respiratory Syncytial Virus, Human / Q000187:drug effects / Q000201:enzymology*; D012259:Ribonuclease, Pancreatic / Q000235:genetics* / Q000378:metabolism; D012260:Ribonucleases; D012452:Saguinus; D014771:Virion / Q000502:physiology
D000998:Antiviral Agents; D011506:Proteins; D011993:Recombinant Fusion Proteins; D004722:Endoribonucleases; D047208:Eosinophil-Derived Neurotoxin; D012260:Ribonucleases; C029494:ribonuclease U; C479221:RNASE2 protein, human; D012259:Ribonuclease, Pancreatic