Huo Yongliang, McConnell Sean C, Liu Shan-Run, Yang Rui, Zhang Ting-Ting, Sun Chiao-Wang, Wu Li-Chen, Ryan Thomas M
Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA.
J Biol Chem. 2009 Feb 20;284(8):4889-96. doi: 10.1074/jbc.M805681200. Epub 2008 Dec 19.
A novel humanized mouse model of Cooley's Anemia (CA) was generated by targeted gene replacement in embryonic stem (ES) cells. Because the mouse does not have a true fetal hemoglobin, a delayed switching human gamma to beta(0) globin gene cassette (gammabeta(0)) was inserted directly into the murine beta globin locus replacing both adult mouse beta globin genes. The inserted human beta(0) globin allele has a mutation in the splice donor site that produces the same aberrant transcripts in mice as described in human cells. No functional human beta globin polypeptide chains are produced. Heterozygous gammabeta(0) mice suffer from microcytic anemia. Unlike previously described animal models of beta thalassemia major, homozygous gammabeta(0) mice switch from mouse embryonic globin chains to human fetal gamma globin during fetal life. When bred with human alpha globin knockin mice, homozygous CA mice survive solely upon human fetal hemoglobin at birth. This preclinical animal model of CA can be utilized to study the regulation of globin gene expression, synthesis, and switching; the reactivation of human fetal globin gene expression; and the testing of genetic and cell-based therapies for the correction of thalassemia.
通过在胚胎干细胞（ES细胞）中进行靶向基因替换，构建了一种新型的人类地中海贫血（CA）人源化小鼠模型。由于小鼠没有真正的胎儿血红蛋白，因此将一个延迟转换的人γ向β(0)珠蛋白基因盒（γβ(0)）直接插入小鼠β珠蛋白基因座，取代了成年小鼠的两个β珠蛋白基因。插入的人β(0)珠蛋白等位基因在剪接供体位点存在突变，在小鼠中产生的异常转录本与人类细胞中描述的相同。不会产生功能性的人β珠蛋白多肽链。杂合γβ(0)小鼠患有小细胞贫血。与先前描述的重型β地中海贫血动物模型不同，纯合γβ(0)小鼠在胎儿期从小鼠胚胎珠蛋白链转换为人胎儿γ珠蛋白。当与人类α珠蛋白敲入小鼠杂交时，纯合CA小鼠出生时仅依靠人类胎儿血红蛋白存活。这种CA临床前动物模型可用于研究珠蛋白基因表达、合成和转换的调控；人类胎儿珠蛋白基因表达的重新激活；以及用于纠正地中海贫血的基因和基于细胞的疗法的测试。
