Long-term expression is essential for virtually all potential gene therapy treatments of neurodegenerative disorders. Some progress has been reported on obtaining long-term expression: Lentivirus vectors have been shown to support expression for 8 months, adeno-associated virus vectors for 6 months, adenovims vectors for 4 months, and helper virus-free HSV-1 vectors for 6 months. Thus, the current levels of long-term expression require significant improvement for human gene therapy applications in the brain. Herpes Simplex Virus (HSV-1) vectors are attractive for gene therapy of neurological disorders because HSV- can persist indefinitely in neurons, because large HSV-1 vectors can co express multiple genes, and because the approximate 150 kb genome of an HSV-1 vector can be viewed as a minichromosome. This laboratory has developed a helper virus-free HSV-1 plasmid vector system for gene transfer into neurons. We have demonstrated long-term (1 year) biochemical and behavioral correction of the rat model of Parkinson's disease by delivery of a HSV-1 vector that expresses human tyrosine hydroxylase (TH) into the partially denervated striatum. The two goals of this proposal are 1) to develop HSV-1 vectors that support significantly higher levels of long-term expression than have been achieved to date using any virus vector system, and 2) to establish general, mechanistic principles for enhancing long-term expression. Our approach is to view the large, approximate 150 kb genome of an HSV-1 vector as a minichromosome. We will use boundary elements to create a euchromatin-like domain, and we will use enhancers to turn on expression from specific promoters located within the euchromatin-like domain. In support of this approach, we have improved long-term expression by inserting one type of boundary element, an insulator, between the vector backbone and a transcription unit. Furthermore, we have shown that addition of an enhancer from the TH promoter to a neurofilament promoter supports long-term (6 months) expression. The first specific aim will isolate specific boundary elements and enhancers that support long-term expression. The second specific aim will investigate the mechanisms by which these elements support tong-term expression. The third specific aim will use these boundary elements and enhancers in combination to construct preferred vectors for long-term expression. Vectors will be evaluated for long-term expression in the rat striatum.

National Institute of Health (NIH)
National Institute of Neurological Disorders and Stroke (NINDS)
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Special Emphasis Panel (ZRG1-BDCN-4 (01))
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Tagle, Danilo A
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Harvard University
Schools of Medicine
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Zhang, Guo-Rong; Zhao, Hua; Cook, Nathan et al. (2017) Characteristic and intermingled neocortical circuits encode different visual object discriminations. Behav Brain Res 331:261-275
Zhang, Guo-Rong; Zhao, Hua; Abdul-Muneer, P M et al. (2015) Neurons can be labeled with unique hues by helper virus-free HSV-1 vectors expressing Brainbow. J Neurosci Methods 240:77-88
Zhang, Guo-rong; Zhao, Hua; Cao, Haiyan et al. (2012) Targeted gene transfer of different genes to presynaptic and postsynaptic neocortical neurons connected by a glutamatergic synapse. Brain Res 1473:173-84
Zhang, Guo-Rong; Zhao, Hua; Choi, Eui M et al. (2012) CaMKII, MAPK, and CREB are coactivated in identified neurons in a neocortical circuit required for performing visual shape discriminations. Hippocampus 22:2276-89
Zhang, Guo-Rong; Zhao, Hua; Cao, Haiyan et al. (2012) Overexpression of either lysine-specific demethylase-1 or CLOCK, but not Co-Rest, improves long-term expression from a modified neurofilament promoter, in a helper virus-free HSV-1 vector system. Brain Res 1436:157-67
Zhang, Guo-Rong; Zhao, Hua; Li, Xu et al. (2011) A 16 bp upstream sequence from the rat tyrosine hydroxylase promoter supports long-term expression from a neurofilament promoter, in a helper virus-free HSV-1 vector system. Brain Res 1415:109-18
Cao, Haiyan; Zhang, Guo-rong; Geller, Alfred I (2011) Antibody-mediated targeted gene transfer of helper virus-free HSV-1 vectors to rat neocortical neurons that contain either NMDA receptor 2B or 2A subunits. Brain Res 1415:127-35
Zhang, Guo-rong; Li, Xu; Cao, Haiyan et al. (2011) The vesicular glutamate transporter-1 upstream promoter and first intron each support glutamatergic-specific expression in rat postrhinal cortex. Brain Res 1377:1-12
Zhang, Guo-rong; Cao, Haiyan; Kong, Lingxin et al. (2010) Identified circuit in rat postrhinal cortex encodes essential information for performing specific visual shape discriminations. Proc Natl Acad Sci U S A 107:14478-83
Zhang, Guo-rong; Geller, Alfred I (2010) A helper virus-free HSV-1 vector containing the vesicular glutamate transporter-1 promoter supports expression preferentially in VGLUT1-containing glutamatergic neurons. Brain Res 1331:12-9

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