INNOVATION:  UCLA researchers have developed a system to greatly amplify the expression of a gene under the ultimate control of a tissue specific promoter. This invention comprises a vector containing 2 main parts: (1) a tissue specific portion containing the strong transactivating fusion protein GAL4-VP16 under the control of a tissue specific promoter and (2) a signal amplification portion utilizing GAL4 binding sites upstream of a protein of interest.

This vector configuration results in the titratible expression of a protein product. With the use of a reporter gene, the invention can be used as a research tool to visualize the expression patterns associated with a particular weak promoter of interest that is otherwise difficult to visualize using currently available technology. In addition, this invention can be used for the expression of therapeutic genes at adjustable levels while maintaining tissue specificity. Significant in vitro and in vivo research has been completed successfully utilizing this system with applications in prostate cancer. In addition, animal models and transgenic mice have successfully been developed.

POTENTIAL APPLICATIONS 

• Research tool for use in cell lines or animal models for noninvasive imaging of tissue-specific gene expression
• Use in gene therapy vectors to track the expression of a gene in vivo or to increase the expression from a tissue specific promoter in vivo
• Monitoring expression patterns of genes under the control of weak promoters
• Separation of promoter-controlled expression timing from protein expression levels

ADVANTAGES

• Gene expression patterns and levels are separate and adjustable using this technology
• Does not significantly perturb the cells/animals being studied
• Any promoter can be studied and any reporter/therapeutic gene can be used this vector
• GAL-4 and VP16 components of the system are thoroughly researched
• Numerous imaging modalities (optical, PET, CCD) can be used to image gene expression using this invention

Related Papers (Selected) Hum Gene Ther. 2006 Jan;17(1):125-32. Bioluminescence imaging of systemic tumor targeting using a prostate-specific lentiviral vector. more... Mol Cancer Ther. 2005 Nov;4(11):1662-9. Imaging androgen receptor function during flutamide treatment in the LAPC9 xenograft model. more... Mol Ther. 2002 Mar;5(3):223-32. Molecular engineering of a two-step transcription amplification (TSTA) system for transgene delivery in prostate cancer. more... Transgenic Res. 2005 Feb;14(1):47-55. Non-invasive imaging of a transgenic mouse model using a prostate-specific two-step transcriptional amplification strategy. more... Proc Natl Acad Sci U S A. 2001 Dec 4;98(25):14595-600. Two-step transcriptional amplification as a method for imaging reporter gene expression using weak promoters. more...

Reference: UCLA Case No. 2002-004

PCT Number: PCT/US03/003847