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.
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.
Sabatino
D E
DE
Hematopoiesis Section, Genetics and Molecular Biology Branch, NHGRI, National Institutes of Health, Bethesda, Maryland 20892, USA.
Wong
C
C
Cline
A P
AP
Pyle
L
L
Garrett
L J
LJ
Gallagher
P G
PG
Bodine
D M
DM
D000818:Animals; D017487:Ankyrins / Q000235:genetics*; D004742:Enhancer Elements, Genetic; D005260:Female; D018628:Gene Dosage; D005914:Globins / Q000235:genetics*; D006801:Humans; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000032:analysis
D017487:Ankyrins; D012333:RNA, Messenger; D005914:Globins