Locus control region-A gamma transgenic mice: a new model for studying the induction of fetal hemoglobin in the adult (original) (raw)
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Genes & Development, 1989
Access the most recent version at doi: 1989 3: 1572-1581 Genes Dev. O Hanscombe, M Vidal, J Kaeda, et al. hemoglobin in murine erythrocytes. human alpha-globin gene in transgenic mice and the production of High-level, erythroid-specific expression of the human References http://genesdev.cshlp.org/content/3/10/1572#related-urls Article cited in: http://genesdev.cshlp.org/content/3/10/1572.refs.html This article cites 26 articles, 7 of which can be accessed free at: service Email alerting click here the top right corner of the article or Receive free email alerts when new articles cite this article -sign up in the box at http://genesdev.cshlp.org/subscriptions go to: Genes & Development To subscribe to
Blood, 1994
Two lines of transgenic mice carrying a normal 40-kb Kpn I &globin cluster transgene lacking the locus control region (LCR) were analyzed for the expression of human y-and pglobin genes during mouse development. After RNase protection assays, the ratios of human ' y-, Ay-, or p-mRNAs relative t o endogenous mouse 5 + a mRNAs were obtained for each stage of development. The two y transgenes were expressed in day-l 1.5 blood (embryonic stage) and day-13.5 blood (early fetal stage), but their expression was markedly decreased by day 16.5 of fetal life. Expression of the p transgene was essentially absent at day 13.5, appeared at a low level by day 16.5, and was maximal by day 18.5, reaching a level similar to that observed in adult mice. Therefore, developmentally regulated expression of the human y-and &globin transgenes was obtained in the absence of the LCR. The relative expression of human y-and @-globin genes was also examined in mice carrying 40-kb Kpn I p-cluster transgenes with two different base substitutions associated with nondeletion forms of hereditary persistence of fetal hemoglobin (HPFH),-202 C+ ' y HPFH and-117 G-A Ay HE HUMAN P-GLOBIN gene cluster is located on the short arm of the chromosome 11. It is composed of five linked functional &like globin genes that span approximately SO kb of DNA and are arranged in the order in which they are expressed developmentally, S'-t-Gy-Ay-6-P-3'. In the early stages of human development, the embryonic yolk sac is the site of hematopoiesis, and the t-gene is the predominant P-like globin gene expressed in erythroid cells. A switch from E-to y-globin gene expression occurs as the site of erythropoiesis changes from yolk sac to fetal liver. A second switch from y-to Sand P-globin gene expression occurs in the perinatal period concomitantly with the establishment of the bone marrow as the major site of hematopoie-s~s. "~ The specific factors that regulate globin gene switching in man are not completely understood, but useful insights have been provided by the study of transgenic mice. Small globin transgenes consisting of the individual human y-or P-globin genes and short segments of their adjacent flanking DNA have been shown to be developmentally regulated in transgenic mice. The y-or 0-globin transgenes were expressed at very low levels and were regulated in a manner similar to that of their murine evolutionary homo-T
An in vivo model for analysis of developmental erythropoiesis and globin gene regulation
The FASEB Journal, 2014
Expression of fetal ␥-globin in adulthood ameliorates symptoms of -hemoglobinopathies by compensating for the mutant -globin. Reactivation of the silenced ␥-globin gene is therefore of substantial clinical interest. To study the regulation of ␥-globin expression, we created the GG mice, which carry an intact 183-kb human -globin locus modified to express enhanced green fluorescent protein (eGFP) from the G␥-globin promoter. GG embryos express eGFP first in the yolk sac blood islands and then in the aorta-gonad mesonephros and the fetal liver, the sites of normal embryonic hematopoiesis. eGFP expression in erythroid cells peaks at E9.5 and then is rapidly silenced (>95%) and maintained at low levels into adulthood, demonstrating appropriate developmental regulation of the human -globin locus. In vitro knockdown of the epigenetic regulator DNA methyltransferase-1 in GG primary erythroid cells increases the proportion of eGFP ؉ cells in culture from 41.9 to 74.1%. Furthermore, eGFP fluorescence is induced >3-fold after treatment of erythroid precursors with epigenetic drugs known to induce ␥-globin expression, demonstrating the suitability of the G␥-globin eGFP reporter for evaluation of ␥-globin inducers. The GG mouse model is therefore a valuable model system for genetic and pharmacologic studies of the regulation of the -globin locus and for discovery of novel therapies for the -hemoglobinopathies.
Experimental Hematology, 2004
Objective. Persistent expression of the human fetal g-globin genes in the adult stage is often associated with naturally occurring deletions in the human b-globin locus. The mapping of the 5′ breakpoints of these deletions within the A gto d-globin intergenic region has suggested that regulatory elements involved in the silencing of the g-globin genes in the adult may be present. We previously identified two elements in this region, termed Enh and F, located 3′ to the A g-globin gene acting as silencers in transient transfection assays. Here, we tested directly the in vivo significance of these elements in the developmental regulation of the human b-like globin genes.
An in vivo model for analysis of developmental erythropoiesis and globin gene regulation
The FASEB Journal, 2014
Expression of fetal ␥-globin in adulthood ameliorates symptoms of -hemoglobinopathies by compensating for the mutant -globin. Reactivation of the silenced ␥-globin gene is therefore of substantial clinical interest. To study the regulation of ␥-globin expression, we created the GG mice, which carry an intact 183-kb human -globin locus modified to express enhanced green fluorescent protein (eGFP) from the G␥-globin promoter. GG embryos express eGFP first in the yolk sac blood islands and then in the aorta-gonad mesonephros and the fetal liver, the sites of normal embryonic hematopoiesis. eGFP expression in erythroid cells peaks at E9.5 and then is rapidly silenced (>95%) and maintained at low levels into adulthood, demonstrating appropriate developmental regulation of the human -globin locus. In vitro knockdown of the epigenetic regulator DNA methyltransferase-1 in GG primary erythroid cells increases the proportion of eGFP ؉ cells in culture from 41.9 to 74.1%. Furthermore, eGFP fluorescence is induced >3-fold after treatment of erythroid precursors with epigenetic drugs known to induce ␥-globin expression, demonstrating the suitability of the G␥-globin eGFP reporter for evaluation of ␥-globin inducers. The GG mouse model is therefore a valuable model system for genetic and pharmacologic studies of the regulation of the -globin locus and for discovery of novel therapies for the -hemoglobinopathies.
Erythroid-specific expression of human beta-globin genes in transgenic mice
The EMBO Journal, 1985
Communicated by R.Flavell Transgenic mice carrying human ,3-globin genes were produced by microinjecting linear DNA molecules containing cloned ,B-globin genes with up to 4300 bp of 5'-flanking sequence and 1700 bp of 3'-flanking sequence. Most (15 of 20) of these transgenic mice expresssed the human ,3-globin genes in blood cells and the level of expression in some mice was comparable with that obtained from endogenous ,B-globin genes. Human (-globin gene expression appeared to be restricted to cells of the erythroid lineage and was first detected between 11 and 14 days of development, in parallel with mouse ,B-globin. Constructs with as little as 48 bp of 5'-flanking sequence also appeared to be expressed appropriately. The mRNA transcripts had correct 5' ends and directed human (3-globin synthesis in reticulocyte lysates. Human ,B-globin protein was detectable in mature erythrocytes from progeny of one of these mice. The frequency and extent of expression was severely depressed when the procaryotic vector DNA was not removed prior to microinjection.
High-level erythroid expression of human alpha-globin genes in transgenic mice
Proceedings of the National Academy of Sciences, 1989
The human alpha 1-globin gene was fused downstream of two erythroid-specific DNase I super-hypersensitive sites that are normally located upstream of the human beta-globin locus. This construct was injected into fertilized mouse eggs, and expression was analyzed in 16-day fetal livers and brains. All 11 fetuses that contained intact copies of the transgene expressed correctly initiated human alpha-globin mRNA in the erythroid fetal liver but not in brain. Levels of expression ranged from 4% to 337% of endogenous mouse beta-globin mRNA. A human alpha-globin construct that did not contain super-hypersensitive sites was not expressed. These results demonstrate that human beta-globin locus activation sequences can stimulate high levels of human alpha-globin gene expression in erythroid tissue of transgenic mice. The results also provide a foundation for experiments designed to coexpress human alpha- and beta-globin genes in transgenic mice and suggest a feasible approach for production ...