Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.653005
Title: Structure and expression of the mouse DNA ligase I gene
Author: Jessop, Joanne Kirsty
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 1995
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Abstract:
46BR is a cell line derived from a patient suffering from immunodeficiency, growth retardation and sunlight sensitivity. DNA replication and repair is affected in 46BR cells which are sensitive to the alkylating agent ethylmethane sulphonate and t 3-aminobenzamide. Aberant DNA ligase I activity has been demonstrated in these cells, and mutations have been identified in both alleles of the DNA ligase I gene. The first mutation specifies a change of glutamate 566 to lysine, a charge alteration which renders the enzyme completely inactive and which could be lethal in a homozygote. The second mutation is a change of arginine 771 to tryptophan which leaves the enzyme with some residual activity. The transformed derivative of 46BR is either hemizygous or homozygous for this second mutation, so cells expressing only this mutant form of DNA ligase I are still viable. This mutation is therefore a good candidate for introduction into the mouse gene in order to create a mouse model for DNA ligase I deficiency. Prior to making a mouse model it was necessary to show that the mutations at the DNA ligase I locus in 46BR give rise to the aberrant cellular phenotype. To do this, wild-type human DNA ligase I cDNA was introduced into 46BR in an expression vector. Selection for transformants was provided by a bacterial neomycin phosphotransferase gene. Transformants were assayed for survival in ethylmethane sulphonate and 3-aminobenzamide, which demonstrated a correlation between the presence of wild-type DNA ligase I sequences within the cells and rescue of sensitivity to these agents. Wild-type human DNA ligase I cDNA therefore complements the defect in 46BR.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.653005  DOI: Not available
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