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Steroid hormone synthesis by a vaccinia enzyme: a new type of virus virulence factor.
Author(s) -
Moore J.B.,
Smith G.L.
Publication year - 1992
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1992.tb05251.x
Subject(s) - biology , vaccinia , virus , virology , open reading frame , microbiology and biotechnology , virulence , viral replication , gene , peptide sequence , biochemistry , recombinant dna
Vaccinia virus open reading frame (ORF) SalF7L has 31% amino acid identity to human 3 beta‐hydroxysteroid dehydrogenase/delta 5‐delta 4 isomerase (3 beta‐HSD). Here we show that SalF7L encodes an active 3 beta‐HSD, by the conversion of pregnenolone to the steroid hormone progesterone. The gene is transcribed early during infection into a 1.4 kb mRNA from an initiation site 12 bp upstream of the ORF. An antiserum raised against bacterially expressed SalF7L immunoprecipitated a 38 kDa polypeptide from infected cells, but not from mock infected cells or from cells infected with a mutant virus from which the SalF7L ORF had been removed. Deletion of the gene had no effect on virus replication in CV‐1 cells in culture, yet the deletion mutant was attenuated when intranasally inoculated into mice. This steroid hormone synthesizing enzyme is a novel type of virus virulence factor.