A minimal ankyrin promoter linked to a human gamma-globin gene demonstrates erythroid specific copy number dependent expression with minimal position or enhancer dependence in transgenic mice

• Published in: The Journal of biological chemistry Vol. 275; no. 37; pp. 28549 - 28554
• Main Authors: Sabatino, D E, Wong, C, Cline, A P, Pyle, L, Garrett, L J, Gallagher, P G, Bodine, D M
• Format: Journal Article
• Language: English
• Published: United States 15.09.2000
• Subjects: Animals; Ankyrins - genetics; copy number; Enhancer Elements, Genetic; Female; g-globin; Gene Dosage; Globins - genetics; Humans; Male; Mice; Mice, Transgenic; Promoter Regions, Genetic; RNA, Messenger - analysis
• ISSN: 0021-9258
• DOI: 10.1074/jbc.M004043200

In red blood cells ankyrin (ANK-1) provides the primary linkage between the erythrocyte membrane skeleton and the plasma membrane. We have previously demonstrated that a 271-bp 5'-flanking region of the ANK-1 gene has promoter activity in erythroid, but not non-erythroid, cell lines. To determine whether the ankyrin promoter could direct erythroid-specific expression in vivo, we analyzed transgenic mice containing the ankyrin promoter fused to the human (A)gamma-globin gene. Sixteen of 17 lines expressed the transgene in erythroid cells indicating nearly position-independent expression. We also observed a significant correlation between the level of Ank/(A)gamma-globin mRNA and transgene copy number. The level of Ank/(A)gamma mRNA averaged 11% of mouse alpha-globin mRNA per gene copy at all developmental stages. The addition of the HS2 enhancer from the beta-globin locus control region to the Ank/(A)gamma-globin transgene resulted in Ank/(A)gamma-globin mRNA expression in embryonic and fetal erythroid cells in six of eight lines but resulted in absent or dramatically reduced levels of Ank/(A)gamma-globin mRNA in adult erythroid cells in eight of eight transgenic lines. These data indicate that the minimal ankyrin promoter contains all sequences necessary and sufficient for erythroid-specific, copy number-dependent, position-independent expression of the human (A)gamma-globin gene.