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Title: Ablation of astrocytes in transgenic mice expressing HSV-thymidine kinase from the mouse GFAP promoter
Author: Bush, T. G.
Awarding Body: University of Cambridge
Current Institution: University of Cambridge
Date of Award: 1997
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To investigate further the functions of astrocytes, a transgenic mouse was generated in which astrocytes can be ablated selectivity. Expression of herpes thymidine kinase (HSV-tk) was targeted to astrocyte using the GFAP promoter. HSV-tk can metabolise anti-herpetic agents, such as ganciclovir (GCV), which results in the formation of toxic moieties that induce cell death. The GFAP promoter cassette was obtained from Lennart Mucke of the Scripps Institute (now UCSF) into which the HSV-tk coding sequence was inserted. A linearised GFAP-HSV-tk construct was microinjected into fertilised mouse eggs to create potential transgenic mice. Four founder animals were identified of which three were capable of transgene transmission. Western blot analysis demonstrated that two lines of mice expressed HSV-tk protein. In one line (7.1), immunohistochemical analysis of brain sections showed that HSV-tk was expressed exclusively in astrocytes and was present in more than 90% of these cells. Neonatal glial cultures derived from this line, demonstrated that transgenic astrocytes were vulnerable to GCV mediated toxicity in vitro. GCV was administered for 14 days following a cortical stab injury. Disruption of both glial scar formation and reformation of the blood-brain barrier was observed. Areas of astrocyte ablation were co-incident with areas of astrocyte proliferation. Thus transgenic astrocytes are vulnerable to GCV mediated toxicity in vivo. In some animals, astrocyte loss was seen also in the hippocampus. In these areas, a secondary loss of neurons was observed consistent with the neurosupportive function of astrocytes. This model system will be useful for studying the effects of astrocyte ablation and disruption of glial scar formation on the regeneration of axons in vivo.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available