http://repub.eur.nl/res/aut/1517/ List of Publications en http://repub.eur.nl/static-eur/img/logo.png http://repub.eur.nl http://repub.eur.nl/res/pub/2508/ 1994-01-01T00:00:00Z We describe the embryonic expression pattern as well as the cloning and initial transcriptional regulatory analysis of the murine (m) GATA-3 gene. In situ hybridization shows that mGATA-3 mRNA accumulation is temporally and spatially regulated during early development: although found most abundantly in the placenta prior to 10 days of embryogenesis, mGATA-3 expression becomes restricted to specific cells within the embryonic central nervous system (in the mesencephalon, diencephalon, pons and inner ear) later in gestation. GATA-3 also shows a restricted expression pattern in the peripheral nervous system, including terminally differentiating cells in the cranial and sympathetic ganglia. In addition to this distinct pattern in the nervous system, mGATA-3 is also expressed in the embryonic kidney and the thymic rudiment, and further analysis showed that it is expressed throughout T lymphocyte differentiation. To begin to investigate how this complex gene expression pattern is elicited, cloning and transcriptional regulatory analyses of the mGATA-3 gene were initiated. At least two regulatory elements (one positive and one negative) appear to be required for appropriate tissue-restricted regulation after transfection of mGATA-3-directed reporter genes into cells that naturally express GATA-3 (T lymphocytes and neuroblastoma cells). Furthermore, this same region of the locus confers developmentally appropriate expression in transgenic mice, but only in a subset of the tissues that naturally express the gene. http://repub.eur.nl/res/pub/2487/ 1993-01-01T00:00:00Z We have carried out a structural and functional analysis on the human NF-L (H-NF-L) gene. It contains a methylation-free island, spanning the 5' flanking sequences and the first exon and a number of neuronal-specific DNase I hypersensitive sites have been identified in the upstream region as well as within the body of the gene. Analysis in cell lines and transgenic mice using a combination of these sites has revealed the presence of a conserved element(s) between -300bp and -190bp which is required for neuronal-specific expression. http://repub.eur.nl/res/pub/2446/ 1989-01-01T00:00:00Z T-lymphocyte development takes place mainly in the thymus, where stromal cells of epithelial and haemopoietic origin are involved in inductive and selective mechanisms, which enable specific lymphocyte populations to migrate to the periphery and establish a network of immune responses. Experiments with intact animals have clarified the precursor-product relationships between thymocyte subpopulations, but the molecular mechanisms of cell interactions in the thymus are difficult to study in vivo. In an attempt to expand thymic cell populations in vivo and maintain them in vitro for such studies, we directed high levels of expression of the murine c-myc proto-oncogene in transgenic mice by inserting it into the mouse Thy-1 transcriptional unit. Such mice develop thymic tumours which contain proliferating thymocytes and, interestingly, expanded populations of epithelial cells. Both cell types can be maintained in vitro. http://repub.eur.nl/res/pub/2405/ 1986-01-01T00:00:00Z The DNA spanning two large deletions in the human beta-globin gene cluster (gamma beta-thalassaemia 1 and 2) has been cloned by cosmid cloning and chromosomal walking. The entire region was mapped and analyzed for the presence of repetitive sequences. The results show that the affected loci have lost almost 100 kb of DNA in a deletion event not involving homologous or repetitive sequences. http://repub.eur.nl/res/pub/2356/ 1983-01-01T00:00:00Z http://repub.eur.nl/res/pub/2364/ 1983-01-01T00:00:00Z The beta-globin gene present on the deletion locus in a Dutch gamma beta-thalassaemic patient was found to be identical to the normal beta-globin gene with respect to DNA sequence and its transcription in HeLa cells. DNase I sensitivity and methylation experiments show that the affected beta-globin gene is present in an inactive configuration in vivo. This is the result of a translocation of a normally inactive locus next to the beta-globin gene on the affected chromosome, or the deletion of sequences which are normally required for the maintenance of the active state. http://repub.eur.nl/res/pub/2368/ 1983-01-01T00:00:00Z Two independent gamma delta beta-thalassemias are each associated with large deletions. We show, by comparing DNA sequences, that the deletions are due to non-homologous DNA exchanges. The 5' breakpoints are located approximately the same distance apart and in the same order along the DNA as their 3' breakpoints. Two independent cases of hereditary persistence of fetal hemoglobin, also involving large deletions, show the same unexpected relationship between their 5' and 3' breakpoints. This relationship is most simply explained if, within each pair, the deletions are of approximately the same length. The results suggest that the four deletions were generated by a common mechanism. Perhaps their 5' and 3' breakpoints are physically close in the nucleus, although far apart on the linear DNA.