Locus control region elements HS2 and HS3 in combination with chromatin boundaries confer high-level expression of a human beta-globin transgene in a centromeric region.
Genes Cells
; 9(11): 1043-53, 2004 Nov.
Article
em En
| MEDLINE
| ID: mdl-15507116
ABSTRACT
Expression constructs are subject to position-effects in transgenic assays unless they harbour elements that protect them from negative or positive influences exerted by chromatin at the site of integration. Locus control regions (LCRs) and boundary elements are able to protect from position effects by preventing heterochromatization of linked genes. The LCR in the human beta-globin gene locus is located far upstream of the genes and composed of several erythroid specific DNase I hypersensitive (HS) sites. Previous studies demonstrated that the LCR HS sites act synergistically to confer position-independent and high-level globin gene expression at different integration sites in transgenic mice. Here we show that LCR HS sites 2 and 3, in combination with boundary elements derived from the chicken beta-globin gene locus, confer high-level human beta-globin gene expression in different chromosomal integration sites in transgenic mice. Moreover, we found that the construct is accessible to nucleases and highly expressed when integrated in a centromeric region. These results demonstrate that the combination of enhancer, chromatin opening and boundary activities can establish independent expression units when integrated into chromatin.
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Base de dados:
MEDLINE
Assunto principal:
Globinas
/
Cromatina
/
Centrômero
/
Transgenes
/
Região de Controle de Locus Gênico
Idioma:
En
Ano de publicação:
2004
Tipo de documento:
Article