Rl. Deresiewicz et al., INTRACELLULAR EXPRESSION OF TOXIC SHOCK SYNDROME TOXIN-1 IN SACCHAROMYCES-CEREVISIAE, Infection and immunity, 62(6), 1994, pp. 2202-2207
In order to search for an occult cytotoxic enzymatic activity of the t
oxic shock syndrome toxin 1 (TSST-1), we placed the gene encoding TSST
-1 (tstH) under the control of an inducible promoter in the eukaryotic
yeast Saccharomyces cerevisiae. Under similar circumstances, the know
n bacterial enzymatic cytotoxins Shiga-like toxin and diphtheria toxin
are both highly lethal to the yeast host. Although full-length stable
TSST-1 was demonstrated within the yeast cells and although it retain
ed mitogenicity for human T cells, it had no apparent effect on the ye
ast cells' growth kinetics or on their gross morphology. Retrieval and
sequencing of the toxin gene revealed the wild-type sequence througho
ut, thus demonstrating that the apparent lack of toxicity for the yeas
t cells was not due to a serendipitous attenuating mutation within the
coding region of the toxin gene. Similar results obtained after a sec
ond transformation of the same strain and after transformation of an u
nrelated strain demonstrate that neither chance permissive host mutati
on nor intrinsic host resistance was likely to have obscured an existi
ng cytotoxic property of TSST-1. We conclude that TSST-1 probably does
not possess a discrete enzymatic property cytotoxic for eukaryotic ce
lls.