Research article

Efficient delivery of Cre-recombinase to neurons in vivo and stable transduction of neurons using adeno-associated and lentiviral vectors

Bushra Y Ahmed^1,2 , Sridhara Chakravarthy³ , Ruben Eggers² , Wim TJMC Hermens² , Jing Ying Zhang⁴ , Simone P Niclou² , Christiaan Levelt³ , Fred Sablitzky⁴ , Patrick N Anderson¹ , AR Lieberman² and Joost Verhaagen²

¹  Department of Anatomy and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK

²  Netherlands Institute for Brain Research, Meibergdreef 33, 1105 AZ Amsterdam, The Netherlands

³  Molecular Visual Plasticity, Netherlands Ophthalmic Research Institute, Netherlands Royal Academy of Arts and Sciences, Meibergdreef 47, 1105 BA Amsterdam, The Netherlands

⁴  Institute of Genetics, School of Biology, Queen's Medical Centre, The University of Nottingham, UK

author email corresponding author email

BMC Neuroscience 2004, 5:4doi:10.1186/1471-2202-5-4

Published:	30 January 2004

Abstract

Background

Inactivating genes in vivo is an important technique for establishing their function in the adult nervous system. Unfortunately, conventional knockout mice may suffer from several limitations including embryonic or perinatal lethality and the compensatory regulation of other genes. One approach to producing conditional activation or inactivation of genes involves the use of Cre recombinase to remove loxP-flanked segments of DNA. We have studied the effects of delivering Cre to the hippocampus and neocortex of adult mice by injecting replication-deficient adeno-associated virus (AAV) and lentiviral (LV) vectors into discrete regions of the forebrain.

Results

Recombinant AAV-Cre, AAV-GFP (green fluorescent protein) and LV-Cre-EGFP (enhanced GFP) were made with the transgene controlled by the cytomegalovirus promoter. Infecting 293T cells in vitro with AAV-Cre and LV-Cre-EGFP resulted in transduction of most cells as shown by GFP fluorescence and Cre immunoreactivity. Injections of submicrolitre quantities of LV-Cre-EGFP and mixtures of AAV-Cre with AAV-GFP into the neocortex and hippocampus of adult Rosa26 reporter mice resulted in strong Cre and GFP expression in the dentate gyrus and moderate to strong labelling in specific regions of the hippocampus and in the neocortex, mainly in neurons. The pattern of expression of Cre and GFP obtained with AAV and LV vectors was very similar. X-gal staining showed that Cre-mediated recombination had occurred in neurons in the same regions of the brain, starting at 3 days post-injection. No obvious toxic effects of Cre expression were detected even after four weeks post-injection.

Conclusion

AAV and LV vectors are capable of delivering Cre to neurons in discrete regions of the adult mouse brain and producing recombination.