Abstract
A 191-kb human bacterial artificial chromosome (BAC) containing the human α-globin genomic locus was used to generate transgenic mice that express, exclusively, human α-globin (huα-globin). Expression of huα-globin reaches a level of 36% of that of endogenous mouse α-globin (muα-globin) on a heterozygous mouse α-thalassemia background (muα-globin knockout, muα+/−). Hemizygous transgenic mice carrying the huα-globin locus on a heterozygous knockout background (huα+/0, muα++/−−) demonstrated complementation of most hematologic parameters. By crossing huα+/0, muα++/−− mice, we were able to generate mice entirely dependent on huα-globin synthesis. Breeding and fluorescent in situ hybridization studies demonstrate that only mice homozygous for the transgene were able to rescue embryonic lethal homozygous muα-globin knockout embryos (muα−−/−−). Adult rescued mice produce hemoglobin at levels similar to wild-type mice, with partial red cell complementation based on mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and red cell distribution width (RDW) measurements. Significant erythrocythemia above wild-type levels seems to be the main compensatory mechanism for the normalization of the hemoglobin levels in the rescued animals. Our studies demonstrate that the huα-globin locus in the 191-kb transgene contains all the necessary elements for the regulated expression of huα-globin in transgenic mice. This animal model should be valuable for studying the mechanisms regulating huα-globin production and for development of therapeutic strategies for β-thalassemia based on downregulation of α-globin expression.
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Acknowledgments
JV is a currently a recipient of a Cooley’s Anemia Research Fellowship from the Cooley’s Anemia Foundation, USA. This work was supported by grants from the Brockhoff Foundation and the National Health and Medical Research Council of Australia. The authors thank Dr Kerry Fowler and Ms Sophie Gazeas for support with the animal work.
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We dedicate this article to the memory of our valued friend and colleague Panayiotis A. Ioannou who passed away during the completion of this work
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Al-Hasani, K., Vadolas, J., Knaupp, A.S. et al. A 191-kb genomic fragment containing the human α-globin locus can rescue α-thalassemic mice. Mamm Genome 16, 847–853 (2005). https://doi.org/10.1007/s00335-005-0089-9
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DOI: https://doi.org/10.1007/s00335-005-0089-9