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Unformatted text preview: been shown that too many insertions of R1 and R2 can decrease insect viability, presumably by interfering with ribosome assembly. GENE THERAPY REVISITED In Chapter 11 , you saw that modified retroviruses have been used in gene-therapy trials to deliver transgenes that may correct certain hu- man diseases. One of the first trials included patients with X-linked severe combined human immunodeficiency dis- ease (SCID), a fatal disease if left untreated because it se- verely compromises the immune system. Bone-marrow cells from each patient were collected and treated with a retrovirus vector containing a good gene for one of the chains of the interleukon-2 receptor (the gene that is mu- tated in these patients), The transformed cells were then infused back into the patient. The immune systems of most of the patients showed significant improvement. However, the therapy had a very serious side effect: two of the patients developed leukemia. In both patients, the retroviral vector had inserted (integrated) near a cellular gene whose aberrant expression is associated with leukemia. A likely scenario is that insertion of the retrovi- ral vector near the cellular gene altered its expression and,...
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This note was uploaded on 01/10/2011 for the course BIOL BIOL taught by Professor Johnson during the Spring '08 term at Aberystwyth University.
- Spring '08