Suppression of a fusion defect by second site mutations in the ecotropic murine leukemia virus surface protein

Tatiana Zavorotinskaya, Lorraine Albritton

Research output: Contribution to journalArticle

44 Citations (Scopus)

Abstract

Entry of ecotropic murine leukemia virus initiates when the envelope surface protein recognizes and binds to the virus receptor on host cells. The envelope transmembrane protein then mediates fusion of viral and host cell membranes and penetration into the cytoplasm. Using a genetic selection, we isolated an infectious retrovirus variant containing three changes in the surface protein - histidine 8 to arginine, glutamine 227 to arginine, and aspartate 243 to tyrosine. Single replacement of histidine 8 with arginine (H8R) resulted in almost complete loss of infectivity, even though the mutant envelope proteins were stable and efficiently incorporated into virions. Virions carrying H8R envelope were proficient at binding cells expressing receptor but failed to induce cell-cell fusion of XC cells, indicating that the histidine at position 8 plays an essential role in fusion during penetration of the host cell membrane. Thus, there is at least one domain in SU that is involved in fusion; the fusion functions do not reside exclusively in TM. In contrast, envelope with all three changes induced cell-cell fusion of XC cells and produced virions that were 10,000-fold more infectious than those containing only the H8R substitution, indicating that changes at positions 227 and 243 can suppress a fusion defect caused by loss of histidine 8 function. Moreover, the other two changes acted synergistically, indicating that both compensate for the loss of the same essential function of histidine 8. The ability of these changes to suppress this fusion defect might provide a means for overcoming postbinding defects found in targeted retroviral vectors for use in human gene therapy.

Original languageEnglish (US)
Pages (from-to)5034-5042
Number of pages9
JournalJournal of Virology
Volume73
Issue number6
StatePublished - 1999

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Murine leukemia virus
Murine Leukemia Viruses
surface proteins
Membrane Proteins
histidine
Histidine
mutation
Mutation
virion
Virion
arginine
cell fusion
Cell Fusion
cells
cell membranes
Arginine
Retroviridae
Cell Membrane
retroviral vectors
Virus Receptors

All Science Journal Classification (ASJC) codes

  • Immunology

Cite this

Suppression of a fusion defect by second site mutations in the ecotropic murine leukemia virus surface protein. / Zavorotinskaya, Tatiana; Albritton, Lorraine.

In: Journal of Virology, Vol. 73, No. 6, 1999, p. 5034-5042.

Research output: Contribution to journalArticle

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