http://repub.eur.nl/res/aut/420/ List of Publications en http://repub.eur.nl/static-eur/img/logo.png http://repub.eur.nl http://repub.eur.nl/res/pub/2469/ 1991-01-01T00:00:00Z Transgenic mice were generated which carried the adult alpha and beta-globin genes and the major tadpole specific beta-globin gene of Xenopus laevis. The adult specific alpha and beta genes were found to express in erythroid tissues in adult mice, while the major tadpole specific beta gene (beta T1) was expressed in blood from 12.5 day embryos. The pattern of expression of the beta T1 gene during mouse development was consistent with its being regulated as an embryonic globin gene in the mouse. This observation suggests that some of the factors mediating globin switching have been conserved during the evolution of modern amphibia and mammals and raises interesting questions concerning the evolution of vertebrate globin gene switching. http://repub.eur.nl/res/pub/2410/ 1987-01-01T00:00:00Z http://repub.eur.nl/res/pub/2411/ 1987-01-01T00:00:00Z We have generated Thy-1.1-transgenic Thy-1.2 mice to study the developmental expression of the Thy-1 gene in detail by transcriptional and immunological methods. In brain, the expression of the injected gene was identical to that of the endogenous gene in a tissue- and development-specific manner. In lymphoid tissue, the transferred gene was also expressed correctly in the early phases of T-cell lineage development; however, as the T cells matured, the transcription of the transferred gene, but not the endogenous gene, was suppressed. This result shows that different regulatory elements are used to express the Thy-1 gene in early and late lymphoid development. http://repub.eur.nl/res/pub/2418/ 1987-01-01T00:00:00Z The human P-globin gene is part of a multigene family and is expressed specifically in adult human erythroid tissue (for review, 1). When the human P-globin is introduced into fertilized mouse eggs, it is first activated in foetal liver and remains expressed in adult erythroid tissues (2,3,4). It therefore mimicks the pattern of expression of its murine counterpart. It has previously been shown in tissue culture (5) and transgenic mice (4) that sequences downstream from the 0-globin promoter are involved in this regulation. We now show that at least part of these sequences are located 0.5-1.2kb downstream from the polyA addition site and constitute a transcriptional enhancer element that is erythroid and developmental specific. http://repub.eur.nl/res/pub/2423/ 1987-01-01T00:00:00Z Hybrid human--mouse Thy-1.1 genes were injected into pronuclei of Thy-1.2 mice to produce transgenic animals. A hybrid gene composed of the 5' part of the mouse Thy-1.1 gene combined with the 3' human untranslated regions was expressed abnormally in the kidney podocytes, which resulted in severe protein-uria and subsequent death in several founder mice. A hybrid Thy-1 gene composed of the human coding region with the 5' and 3' flanking regions of the mouse gene was expressed abnormally in a different part of the kidney (the tubular epithelia), which resulted in a proliferative kidney disorder. In addition, a neoplasm was found in the brain of one of these mice. These results show that the Thy-1 protein can play an important role in the activation, proliferation, and differentiation of many different cell types. http://repub.eur.nl/res/pub/2425/ 1987-01-01T00:00:00Z We have constructed a "minilocus" that contains the 5' and 3' flanking regions of the human beta-globin locus and the beta-globin gene. These regions are characterized by erythroid-specific DNAase I-superhypersensitive sites and are normally located approximately 50 kb 5' and 20 kb 3' of the beta-globin gene. This minilocus is expressed tissue-specifically in transgenic mice at a level directly related to its copy number yet independent of its position of integration in the genome. Moreover, the expression per gene copy is the same in each mouse and as high as that of the endogenous mouse beta-globin gene. These results indicate that the DNA regions flanking the human beta-globin locus contain dominant regulatory sequences that specify position-independent expression and normally activate the complete human multigene beta-globin locus. http://repub.eur.nl/res/pub/2401/ 1986-01-01T00:00:00Z We have introduced the human fetal gamma- and adult beta-globin genes into the germ line of mice. Analysis of the resulting transgenic mice shows that the human gamma-globin gene is expressed like an embryonic mouse globin gene; the human beta-globin gene is expressed (as previously shown) like an adult mouse globin gene. These results imply that the regulatory signals for tissue- and developmental stage-specific expression of the globin genes have been conserved between man and mouse but that the timing of the signals has changed. Because the two genes are expressed differently, we introduced a hybrid gamma beta-globin gene construct. The combination of the regulatory sequences resulted in the expression of the hybrid gene at all stages in all the murine erythroid tissues. http://repub.eur.nl/res/pub/2404/ 1986-01-01T00:00:00Z We have introduced a mouse Thy-1.1 gene into the germline of Thy-1.2 mice. The introduced gene was shown to be expressed at very high levels in thymocytes when compared with the endogenous gene. Transgenic thymocytes were shown to evoke a higher than normal primary anti-Thy-1.1 antibody response in plaque-forming cell (PFC) assays. This result suggests that a direct quantitative interaction of the Thy-1 antigen activates the B cell response. http://repub.eur.nl/res/pub/2409/ 1986-01-01T00:00:00Z The Thy-1 gene is expressed in a tissue- and stage-specific pattern and has a typical 1.6kb methylation-free island (MFI) covering about 600bp upstream and downstream of the two alternative first exons. By microinjection of a mouse Thy-1.1/human Thy-1 gene into fertilized eggs, we were able to show that the MFI is restored in the transgenic mice. The flanking sequence became methylated, but the MFI remains unmethylated in all tissues of transgenic mice at different developmental stages tested, irrespective of the site of expression of the gene. There is one exception, in extra-embryonal tissues of 14.5 day embryos a small percentage of the islands were methylated. We conclude that maintenance of the MFI is regulated by cis-acting sequences present within the gene, and indicates that the unmethylated state of the islands is consistent with a necessary but not sufficient condition for expression of the gene. http://repub.eur.nl/res/pub/2394/ 1985-01-01T00:00:00Z