Prolonged in vivo gene expression driven by a tyrosine hydroxylase promoter in a defective herpes simplex virus amplicon vector.
A 9.0-kb fragment of the tyrosine hydroxylase (TH) promoter, previously shown to direct tissue-specific expression in transgenic mice, was fused to an Escherichia coli LacZ reporter gene in a defective herpes simplex virus type-1 (HSV-1) amplicon vector (THlac). The HSV immediate early (IE) 4/5 promoter (HSVlac) was used as a control. LacZ gene expression was visualized by X-Gal histochemical and TH immunocytochemical analysis. Two days and 10 weeks after THlac injection into rat caudate nucleus (CN), X-Gal-stained cells were observed in the substantia nigra (SN) and locus ceruleus (LC) ipsilateral to the injection site. These blue cells were TH-positive neurons as evidenced by double labeling with immunocytochemistry. Moreover, the number of X-Gal+, TH+ (double-positive) neurons in the SN increased at 10 weeks as compared to that seen 2 days after THlac injection. In marked contrast, few double-positive nigral neurons were observed either 2 days or 10 weeks after direct injection of THlac into SN. However, neither nigral nor striatal injection of HSVlac resulted in prolonged gene expression. These results suggest that a neuronal, but not a viral, promoter in an HSV vector can produce cell-type-specific, prolonged, and stable gene expression following retrograde transport. In addition, THlac produced infrequent gene expression in TH-negative cells (CN and dorsal to SN) after THlac injection into CN and SN, respectively. Overall, these results suggest that in some in vivo contexts cell-type-preferred expression can be achieved by a cellular promoter in an amplicon vector. Moreover, they underscore the need for the careful and systematic study of neuronal promoters in HSV vectors.
Jin
B K
BK
Laboratory of Molecular Neurobiology, Cornell University Medical College, Burke Research Medical Institute, White Plains, NY 10605, USA.
Belloni
M
M
Conti
B
B
Federoff
H J
HJ
Starr
R
R
Son
J H
JH
Baker
H
H
Joh
T H
TH
D003673:Defective Viruses; D015870:Gene Expression; D005822:Genetic Vectors; D018259:Herpesvirus 1, Human / Q000235:genetics*; D006801:Humans; D007267:Injections; D011401:Promoter Regions, Genetic; D013997:Time Factors; D014446:Tyrosine 3-Monooxygenase / Q000235:genetics*; D001616:beta-Galactosidase / Q000235:genetics
D014446:Tyrosine 3-Monooxygenase; D001616:beta-Galactosidase