Improvement To Retroviral Vectors Containing The Human Ubiquitin C Promoter

Summary

UCLA researchers in the Department of Molecular Biology have developed a lentiviral vector, “pCCLc-roUBC”, containing the cellular promoter from the human ubiquitin C gene (UBC), to improve transgene expression in retroviral vectors.

Background

Gene delivery into human cells is a promising way to correct or protect against genetic alterations in a variety of human diseases such as hematological malignancies.  Various gene transduction systems have been developed, including gamma-retroviral vectors, lentiviral vectors, adenoviral vectors and adeno-associated viral vectors.  However, despite the diversity of vector systems, cell transduction and transgene expression efficiency can still be too low for therapeutic efficacy.  Thus, high-level expression of transgenes in the majority of target cells remains a significant challenge for gene transfer technology.

Innovation

UCLA researchers have developed a lentiviral vector, “pCCLc-roUBC”, that addresses potential needs for higher transgene expression in lentiviral vectors that contain internalr promoters.  This human ubiquitin C (UBC) promoter is oriented in a reverse orientation so that the direction of transcription from the said promoter is oriented towards the 5′ long terminal repeat (LTR).  Upon lentiviral transduction of target cells, this roUBC vector retains its intron and expresses transgenes at an approximately four-fold higher level than vectors with a UBC promoter oriented such that transcription progressed towards the 3’ LTR.  The UBC promoter direction reversal also improves expression from bidirectional vectors, which is demonstrated by the increased expression of EGFP in a bidirectional vector with a reversed UBC promoter in comparison to the forward oriented counterpart.  The utility of this promoter orientation is not limited to the PCCLc lentriviral vector and would be beneficial in other lenti- and retroviral vectors as well.

Applications

• Gene delivery
• Lentiviral vectors

Advantages

• Transgene expression four-fold higher than vectors containing UBC promoter with different (forward) orientation
• Improves expression from bidirectional vectors, increased expression of EGFP

Patent Status