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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
21
pubmed:dateCreated
2005-10-19
pubmed:abstractText
The development of oncoretrovirus vectors for human gamma-globin has been hampered by problems of low expression and gene silencing. In order to address these problems, we investigated an enhancer element identified from individuals with deletional hereditary persistence of fetal hemoglobin 2 (HPFH2), a genetic condition characterized by elevated levels of gamma-globin in adults. Plasmid transfection studies in erythroid MEL (murine erythroleukemia) cells demonstrated the HPFH2 element could function synergistically with the beta-globin locus control region to enhance the expression of an Agamma-globin gene with a truncated -382 bp promoter. A series of oncoretrovirus vectors were subsequently generated that contain an expression cassette for Agamma-globin linked to various combinations of the HPFH2 enhancer, the alpha-globin HS40 enhancer, and several versions of the promoter from Agamma-globin or beta-globin. Expression analysis in transduced MEL cell clones revealed very high levels of promoter-autonomous silencing that was at least partially abrogated by the HPFH2 enhancer. The vector containing a combination of a -201 bp Agamma-globin gene promoter with the Greek HPFH -117 point mutation and both the HPFH2 and HS40 enhancers exhibited no signs of vector silencing and was expressed at 248+/-99% per copy of mouse alpha-globin (62% of total alpha-globin). This represents a significant improvement over previously reported oncoretrovirus vectors for Agamma-globin, and demonstrates the capacity of the HPFH2 enhancer to abrogate sequence-autonomous silencing of the Agamma-globin promoter in the context of a gene transfer vector.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0969-7128
pubmed:author
pubmed:issnType
Print
pubmed:volume
12
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1591-600
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
2005
pubmed:articleTitle
Use of the hereditary persistence of fetal hemoglobin 2 enhancer to increase the expression of oncoretrovirus vectors for human gamma-globin.
pubmed:affiliation
Institute of Molecular Biology and Biotechnology, F.O.R.T.H., Heraklion, Greece.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't, Research Support, N.I.H., Extramural