Generation and Characterization of a Transgenic Mouse Carrying a Functional Humanβ-Globin Gene with the IVSI-6 Thalassemia Mutation

Abstract

Mouse models that carry mutations causing thalassemia represent a suitable tool to test in vivo new mutation-specific therapeutic approaches. Transgenic mice carrying the β-globin IVSI-6 mutation (the most frequent in Middle-Eastern regions and recurrent in Italy and Greece) are, at present, not available. We report the production and characterization of a transgenic mouse line (TG-β-IVSI-6) carrying the IVSI-6 thalassemia point mutation within the human β-globin gene. In the TG-β-IVSI-6 mouse (a) the transgenic integration region is located in mouse chromosome 7; (b) the expression of the transgene is tissue specific; (c) as expected, normally spliced human β-globin mRNA is produced, giving rise to β-globin production and formation of a human-mouse tetrameric chimeric hemoglobin mu α-globin2/hu β-globin2 and, more importantly, (d) the aberrant β-globin-IVSI-6 RNAs are present in blood cells. The TG-β-IVSI-6 mouse reproduces the molecular features of IVSI-6 β-thalassemia and might be used as an in vivo model to characterize the effects of antisense oligodeoxynucleotides targeting the cryptic sites responsible for the generation of aberrantly spliced β-globin RNA sequences, caused by the IVSI-6 mutation. These experiments are expected to be crucial for the development of a personalized therapy for β-thalassemia.

RNA Splicing and Disease: Animal Models to Therapies

“…Lewis and colleagues were the first to successfully generate a humanized mouse model of βthalassemia that expresses an aberrant splice variant by carrying common IVSII-654 β-thalassemia splicing mutation [76]. More recently, subsequent models were generated harboring additional splice-disrupting mutations [77, 78]. Importantly, not only were these models useful for gaining further understanding of the molecular mechanisms involved with the disease, but also as a platform for testing splice switching oligonucleotides [79].…”