GADD34 gene restores virulence in viral vector used in experimental stroke study.

GADD34 is expressed in the ischaemic brain and reverses protein synthesis shutdown. Consequently, GADD34 could have neuroprotective potential in stroke. BHK medium, a replication-deficient HSV viral vector (HSV1716) with no insert or containing full-length GADD34, the N terminal or a conserved portion of the gene, was injected into mouse brain before stroke. Infarct size was 1.0+/-0.26, 1.19+/-0.36, 1.5+/-0.36, 1.3+/-0.36, and 1.1+/-0.28 mm3, respectively. The increase in infarct size with full-length GADD34 was statistically significant (P<0.05). Immunohistochemistry confirmed viral protein expression. Tissue culture studies revealed GADD34 gene restored virulence in HSV1716, suggesting that HSV virulence, rather than increased GADD34, exacerbated ischaemic damage.