Amelioration of retroviral vector silencing in locus control region β- globin-transgenic mice and transduced F9 embryonic cells

Cameron S. Osborne, Peter Pasceri, Rakesh Singal, Tanya Sukonnik, Gordon D. Ginder, James Ellis

Research output: Contribution to journalArticle

55 Citations (Scopus)

Abstract

Retroviral vectors are transcriptionally silenced in hematopoietic stem cells, and this phenomenon must be overcome for effective gene therapy of blood diseases. The murine stem cell virus (MSCV) vector completely silences β-globin reporter genes regulated by locus control region (LCR) elements 5'HS2 to 5'HS4 in seven of eight transgenic mice. Here, we show that no single known MSCV silencer element is sufficient for complete LCR β-globin transgene silencing. However, partial silencing of high-copy transgenes is conveyed by the MSCV direct repeat and promoter elements. The CpG methylation pattern of silenced and expressed MSCV promoter transgenes is virtually identical, demonstrating that silencing does not absolutely correlate with methylation status. Combined mutations in all four MSCV silencer elements leads to expression of β-globin in 6 of 10 transgenic mice. The same mutations incorporated into the HSC1 retrovirus vector direct neogene expression in 71% of transduced F9 embryonic carcinoma cells. These studies demonstrate that combined mutation of four retroviral silencer elements relieves complete silencing in most transgenic mice and transduced F9 cells and suggests that novel silencer elements remain. Enhanced expression of the HSC1 vector in primitive stem cells is well suited for blood gene therapy applications.

Original languageEnglish
Pages (from-to)5490-5496
Number of pages7
JournalJournal of Virology
Volume73
Issue number7
StatePublished - Jan 1 1999
Externally publishedYes

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Locus Control Region
retroviral vectors
Globins
Transcriptional Silencer Elements
Transgenic Mice
Stem Cells
genetically modified organisms
stem cells
loci
Viruses
mice
Transgenes
viruses
cells
transgenes
Genetic Therapy
Methylation
Mutation
gene therapy
mutation

ASJC Scopus subject areas

  • Immunology

Cite this

Amelioration of retroviral vector silencing in locus control region β- globin-transgenic mice and transduced F9 embryonic cells. / Osborne, Cameron S.; Pasceri, Peter; Singal, Rakesh; Sukonnik, Tanya; Ginder, Gordon D.; Ellis, James.

In: Journal of Virology, Vol. 73, No. 7, 01.01.1999, p. 5490-5496.

Research output: Contribution to journalArticle

Osborne, Cameron S. ; Pasceri, Peter ; Singal, Rakesh ; Sukonnik, Tanya ; Ginder, Gordon D. ; Ellis, James. / Amelioration of retroviral vector silencing in locus control region β- globin-transgenic mice and transduced F9 embryonic cells. In: Journal of Virology. 1999 ; Vol. 73, No. 7. pp. 5490-5496.
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