The general approach of gene therapy is nothing more than an extension of the technique for clone selection by functional complementation (Chapter 12). The functions absent in the recipient as a result of a defective gene are introduced on a vector that inserts into one of the recipients chromosomes and thereby generates a transgenic animal that has been genetically cured. The technique is of great potential in humans because it offers the hope of correcting hereditary diseases. However, gene therapy is also being applied to mammals other than humans. The first example of gene therapy in a mammal was the correction of a growth-hormone deficiency in mice. The recessive mutation little (lit) results in dwarf mice. Even though a mouses growth-hormone gene is present and apparently normal, no mRNA for this gene is produced. The initial step in correcting this deficiency was to inject homozygous lit/lit eggs with about 5000 copies of a 5-kb linear DNA fragment that contained the rat growth-hormone structural gene (RGH) fused to a regulatorpromoter sequence from a mouse metallothionein gene (MP). The normal job of metallothionein is to detoxify heavy metals, so the regulatory sequence is responsive to the presence of heavy metals in the … Continue reading →

PUBLIC RELEASE DATE: 7-Jul-2014 Contact: Meng Zhao eic@nrren.org 86-138-049-98773 Neural Regeneration Research Because the adult mammalian central nervous system has only limited intrinsic capacity to regenerate connections after injury, due to factors both intrinsic and extrinsic to the mature neuron, therapies are required to support the survival of injured neurons and to promote the long-distance regrowth of axons back to their original target structures. The retina and optic nerve are part of the CNS and this system is much used in experiments designed to test new ways of promoting regeneration after injury. Testing of therapies designed to improve RGCs viability also has direct clinical relevance because there is loss of these centrally projecting neurons in many ophthalmic diseases. Many different approaches are being trialed, targeting different receptor systems and/or different signaling pathways, some aimed at enhancing intrinsic growth capacity in injured RGCs, others aimed at reducing the impact of factors external to the neuron that suppress/restrict the regenerative response. An approach increasingly of interest involves the use of modified, replication-deficient viral vectors to introduce appropriate genes into injured cells in the visual pathway (gene therapy). In the perspective article written by Prof Alan Harvey, from School of Anatomy, Physiology and … Continue reading →