A 191-kb genomic fragment containing the human alpha-globin locus can rescue alpha-thalassemic mice.

Abstract

A 191-kb human bacterial artificial chromosome (BAC) containing the human alpha-globin genomic locus was used to generate transgenic mice that express, exclusively, human alpha-globin ((hu)alpha-globin). Expression of (hu)alpha-globin reaches a level of 36% of that of endogenous mouse alpha-globin ((mu)alpha-globin) on a heterozygous mouse alpha-thalassemia background ((mu)alpha-globin knockout, (mu)alpha(+/-)). Hemizygous transgenic mice carrying the (hu)alpha-globin locus on a heterozygous knockout background ((hu)alpha(+/0), (mu)alpha(++/--)) demonstrated complementation of most hematologic parameters. By crossing (hu)alpha(+/0), (mu)alpha(++/--) mice, we were able to generate mice entirely dependent on (hu)alpha-globin synthesis. Breeding and fluorescent in situ hybridization studies demonstrate that only mice homozygous for the transgene were able to rescue embryonic lethal homozygous (mu)alpha-globin knockout embryos ((mu)alpha(--/--)). 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 (hu)alpha-globin locus in the 191-kb transgene contains all the necessary elements for the regulated expression of (hu)alpha-globin in transgenic mice. This animal model should be valuable for studying the mechanisms regulating (hu)alpha-globin production and for development of therapeutic strategies for beta-thalassemia based on downregulation of alpha-globin expression.

• Authors: Keith Al-Hasani, Jim Vadolas, Anja S Knaupp, Hady Wardan, Lucille Voullaire, Robert Williamson, Panayiotis A Ioannou
• Journal: Mammalian genome : official journal of the International Mammalian Genome Society (Mamm Genome) Vol. 16 Issue 11 Pg. 847-53 (Nov 2005) ISSN: 0938-8990 [Print] United States
• PMID: 16284800 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Globins

Topics

• Animals
• Chromatography, High Pressure Liquid
• Chromosomes, Artificial, Bacterial (genetics)
• Chromosomes, Mammalian (genetics)
• Crosses, Genetic
• Disease Models, Animal
• Globins (deficiency, genetics)
• Humans
• In Situ Hybridization, Fluorescence
• Mice
• Mice, Knockout
• Mice, Transgenic
• Transgenes (genetics)
• alpha-Thalassemia (genetics)