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D Meijer

Publications and source records attributed to D Meijer.

33 records · Page 2Linked to original sources
PubMed1992

Mapping the transactivation domain of the Oct-6 POU transcription factor.

The POU transcription factor Oct-6 is expressed in embryonic stem cells, glial progenitor cells and in a restricted set of neurons in the CNS. The protein has been shown to act as a transactivator as well as a repressor. Here we show that the Oct-6 protein activates transcription from three different promoters in HeLa cells. The ability to activate a minimal tk promoter via a multimerized IgH enhancer octamer motif relies on a domain within the aminoterminal third of the protein. Parts of this domain can be deleted without abolishing transactivation, suggesting that there is functional redundancy within this region. The transactivation domain of the Oct-6 protein is different from other described activation domains in that it is highly glycine and alanine rich.

Animals↗
PubMed1992

Genetic variability of the murine creatine kinase B gene locus and related pseudogenes in different inbred strains of mice.

The role of genetic variation in isoenzyme gene families is often poorly appreciated. We report here on the determination of DNA sequences and typing of genetic variability in four creatine kinase B (CKB) gene loci in different inbred strains of mice. The unique functional murine CKB gene was found to be nearly identical to the previously characterised rat and human sequences in both size and exon-intron structure. In this gene, approximately 0.5% allelic nucleotide positions as well as the lengths of simple A-rich and [TG]n repetitive elements located at the 5' and 3' sides of the transcribed segment, differed between inbred strains of mice. Preliminary experiments suggest that this sequence divergence is of importance for design of gene targeting strategies involving homologous DNA recombination. The three additional CKB-like gene loci in mice all had the characteristics of processed pseudogenes. By Southern blot analysis we could demonstrate that both the type and number of pseudogenes differed between inbred strains. Analysis of the CKB gene sequences enabled us to speculate about the evolutionary history of this highly polymorphic subfamily of genes.

Amino Acid Sequence↗
PubMed1992

Clinical studies of Ukrain in terminal cancer patients (phase II).

Phase II of clinical studies was performed on 70 patients, ranging in age from 14 to 80 years, (27 male, 43 female) to determine the appropriate dose range for Ukrain and the clarification of dose/response relationships, in order to provide an optimal background for wider therapeutic trials. The following parameters were studied: physiological (pulse, blood pressure, temperature); biochemical, haematological and immunological. Electrolytes and trace elements were investigated, as well as neopterin, tumour markers, immune complexes, non specific blocking factors, development of tumours and metastases in quantitative respects (by X-ray, CT, scintigrams and US). The patients' general conditions were also assessed. Ukrain was given intramuscularly or intravenously every one, two, three, four or five days, or according to other schemata, in the dose range of 2.5, 5, 10, 15, 20 or 25 mg increasing (2.5 to 25 mg per injection), decreasing (25 to 2.5 mg per injection) and stable (5, 10, 15, 20 or 25 mg per injection). Duration of one course of therapy was between 10 days and 90 days. Intervals between courses ranged from 7 days to 3 months. In order to find dose/duration/interval/response-relationships, some cases were treated after chemoradiotherapy, some as adjuvant therapy to chemo-radiotherapy and alternatives such as iscador, and some as monotherapy. All patients were at terminal stages of their disease.

Adolescent↗
PubMed1992

Ukrain both as an anti cancer and immunoregulatory agent.

Thirty six stage III cancer patients were treated with Ukrain, a semisynthetic drug derived from Chelidonium majus L. alkaloids conjugated with thiophosphoric acid. The drug was injected intravenously every second day in a dose of 10 mg per injection. Each patient received 300 mg of the drug (30 injections). The cytostatic effect of Ukrain was monitored clinically and by ultrasonography (USG) and computer tomography (CT), as well as by determination of CEA and CA-125 in the sera of patients with rectal and ovarian cancers, respectively. The influence of Ukrain on immune parameters was evaluated by monoclonal antibodies (MAb) to CD2, CD4, CD8 and CD22. The influence of Ukrain on immune parameters in cancer patients was matched with its effect on these parameters in 20 healthy volunteer controls. The results obtained indicate that Ukrain, in a concentration not cytostatic in normal cells, is cytostatic for malignant ones, and may suppress the growth of cancer. The compound also has immunoregulatory properties, regulating the T lymphocyte subsets.

Adjuvants, Immunologic↗
PubMed1991

Hepatic resection: haemostatic control by means of compression sutures: a new method.

Blood loss during partial hepatic resection is a major concern. Controlling haemorrhage by means of non-cutting compression sutures, without the risk of disrupting the liver tissue, was experimentally investigated. Twenty-two beagles underwent a partial resection of the right median liver lobe with this technique. Blood loss was negligible and no complications occurred during surgery or follow-up. There were no deaths. The method of using compression sutures is a simple, quick and efficient technique to prevent blood loss during and after partial hepatic resection.

Animals↗
PubMed1990

The octamer binding factor Oct6: cDNA cloning and expression in early embryonic cells.

We have cloned a cDNA encoding a novel octamer binding factor Oct6 that is expressed in undifferentiated ES cells. Expression of the Oct6 gene is downregulated upon differentiation of these cells by aggregate formation. Furthermore the gene is transiently up regulated during retinoic acid induced differentiation of P19 EC cells, reaching maximum levels of expression one day after RA addition. Sequence analysis of the cDNA encoding the Oct6 protein indicated that the Oct6 gene is a member of the POU-HOMEO domain gene family. The gene expresses a 3 kb mRNA encoding a 449 amino acid protein with an apparent molecular weight of 45 kD. The sequence of the Oct6 POU domain is identical to that of the rat SCIP (Tst-1) gene. The Oct6 expression pattern suggests a role for this DNA binding protein in neurogenesis as well as early embryogenesis.

Amino Acid Sequence↗
PubMed1990

The rat androgen receptor gene promoter.

The androgen receptor (AR) is activated upon binding of testosterone or dihydrotestosterone and exerts regulatory effects on gene expression in androgen target cells. To study transcriptional regulation of the rat AR gene itself, the 5' genomic region of this gene was cloned from a genomic library and the promoter was identified. S1-nuclease protection analysis showed two major transcription start sites, located between 1010 and 1023 bp upstream from the translation initiation codon. The area surrounding these start sites was cloned in both orientations in a CAT reporter plasmid. Upon transfection of the constructs into COS cells, part of the promoter stimulated transcription in an orientation-independent manner, but the full promoter showed a higher and unidirectional activity. In the promoter/reporter gene constructs, transcription initiated from the same positions as in the native gene. Sequence analysis showed that the promoter of the rat AR gene lacks typical TATA and CCAAT box elements, but one SP1 site is located at about 60 bp upstream from the major start site of transcription. Other possible promoter elements are TGTYCT sequences at positions -174 to -179, -434 to -439., -466 to -471, and -500 to -505, resembling half-sites of the glucocorticoid-responsive element (GRE). Furthermore, a homopurine stretch containing a total of 8 GGGGA elements and similar to sequences that are present in several other GC-rich promoters, is located between -89 and -146 bp upstream from the major start site of transcription.

Animals↗
PubMed1990

Mouse "protective protein". cDNA cloning, sequence comparison, and expression.

The "protective protein" is the glycoprotein that forms a complex with the lysosomal enzymes beta-galactosidase and neuraminidase. Its deficiency in man leads to the metabolic storage disorder galactosialidosis. The primary structure of human protective protein, deduced from its cloned cDNA, shows homology to yeast serine carboxypeptidases. We have isolated a full-length cDNA encoding murine protective protein. The nucleotide sequences as well as the predicted amino acid sequences are highly conserved between man and mouse. Domains important for the protease function are completely identical in the two proteins. Both human and mouse mature protective proteins covalently bind radiolabeled diisopropyl fluorophosphate. Transient expression of the murine cDNA in COS-1 cells yields a protective protein precursor of 54 kDa, a size characteristic of the glycosylated form. This cDNA-encoded precursor, endocytosed by human galactosialidosis fibroblasts, is processed into a 32- and a 20-kDa heterodimer and corrects beta-galactosidase and neuraminidase activities. A tissue-specific expression of protective protein mRNA is observed when total RNA from different mouse organs is analyzed on Northern blots.

Amino Acid Sequence↗
PubMed1990

Chronic myeloid leukemia may be associated with several bcr-abl transcripts including the acute lymphoid leukemia-type 7 kb transcript.

In the majority of Philadelphia (Ph)-positive chronic myeloid leukemia (CML) patients, the c-abl gene is fused to the bcr gene, resulting in the transcription of an 8.5 kb chimeric bcr-abl mRNA, which is translated into a p210bcr-abl fusion protein. In about 50% of the Ph-positive acute lymphoid leukemias (ALL), the bcr-abl gene fusion is identical to CML, while in 50% an alternative fusion between these two genes occurs, in which the central bcr-sequences are absent. This results in transcription of a 7 kb bcr-abl mRNA, encoding a P190bcr-abl fusion protein. Cloning and sequencing of the chimeric part of bcr-abl cDNAs from two Ph-positive CML patients in chronic phase showed that in one patient, as in the Ph-positive ALL, all central bcr sequences are absent, while in the other patient, part of the bcr central sequences are deleted. Therefore, we speculate that the presence of the 7 kb chimeric ALL type mRNA in one of the patients is not sufficient to drive an acute rather than a chronic leukemic process in this case. The deletions of the central bcr-sequences described here define the minimal sequence requirement of the bcr-abl fusion gene in CML patients so far.

Amino Acid Sequence↗
PubMed1988

Evolution and mutagenesis of the mammalian excision repair gene ERCC-1.

The human DNA excision repair protein ERCC-1 exhibits homology to the yeast RAD10 repair protein and its longer C-terminus displays similarity to parts of the E. coli repair proteins uvrA and uvrC. To study the evolution of this 'mosaic' ERCC-1 gene we have isolated the mouse homologue. Mouse ERCC-1 harbors the same pattern of homology with RAD10 and has a comparable C-terminal extension as its human equivalent. Mutation studies show that the strongly conserved C-terminus is essential in contrast to the less conserved N-terminus which is even dispensible. The mouse ERCC-1 amino acid sequence is compatible with a previously postulated nuclear location signal and DNA-binding domain. The ERCC-1 promoter harbors a region which is highly conserved in mouse and man. Since the ERCC-1 promoter is devoid of all classical promoter elements this region may be responsible for the low constitutive level of expression in all mouse tissues and stages of embryogenesis examined.

Amino Acid Sequence↗
PubMed1987

Molecular characterization of the testis specific c-abl mRNA in mouse.

The c-abl gene encodes a protein tyrosine kinase and is transcribed from at least two promoters giving rise to transcripts of two size classes of approximately 5 and 6 kb in length. These mRNAs only differ in their most 5' exon and encode proteins of similar size but with different N-termini. In the mouse testis an additional abundant c-abl mRNA of 4 kb is detected. This mRNA was shown to be expressed in the haploid male germ cells of the adult mouse. Here we describe the cloning and molecular characterization of a cDNA representing the testis specific c-abl transcript. We show that the 4 kb c-abl mRNA arises from alternative polyadenylation of an RNA transcribed from the same promoter as the 5 kb mRNA. The site of polyadenylation is unusual in this shorter transcript as it is not preceded by the highly conserved hexanucleotide AAUAAA. The use of this polyadenylation site removes 1.2 kb of 3' sequences present in the somatic c-abl mRNAs, but does not affect the main open reading frame of the transcript. Using in situ hybridization on whole testis sections it is shown that the 4 kb c-abl mRNA is most abundant in the elongating spermatids.

Animals↗
PubMed1987

Unique fusion of bcr and c-abl genes in Philadelphia chromosome positive acute lymphoblastic leukemia.

The Philadelphia (Ph) chromosome, the product of t(9:22), is the cytogenetic hallmark of chronic myelogenous leukemia. The c-abl oncogene on chromosome 9 is translocated to the Ph chromosome and linked to a breakpoint cluster region (bcr), which is part of a large bcr gene. This results in the formation of a bcr-c-abl fusion gene, which is transcribed into an 8.5 kb chimeric mRNA encoding a 210 kd bcr-c-abl fusion protein. The Ph chromosome is also found in acute lymphoblastic leukemia (Ph+ ALL). Although the c-abl is translocated and a new 190 kd c-abl protein has been identified, no breakpoints are observed in the bcr (Ph+bcr- ALL). Here we show that in Ph+bcr- ALL, breakpoints in chromosome 22 occur within the same bcr gene, but more 5' of the bcr. Cloning of a chimeric bcr-c-abl cDNA demonstrates that the fusion gene is transcribed into a 7 kb mRNA, encoding a novel fusion protein.

Base Sequence↗
PubMed1987

The structure of a human neurofilament gene (NF-L): a unique exon-intron organization in the intermediate filament gene family.

We have cloned and determined the nucleotide sequence of the human gene for the neurofilament subunit NF-L. The cloned DNA contains the entire transcriptional unit and generates two mRNAs of approx. 2.6 and 4.3 kb after transfection into mouse L-cells. The NF-L gene has an unexpected intron-exon organization in that it entirely lacks introns at positions found in other members of the intermediate filament gene family. It contains only three introns that do not define protein domains. We discuss possible evolutionary schemes that could explain these results.

Amino Acid Sequence↗
PubMed1977

Plasma catecholamines via an improved fluorimetric assay: comparison with an enzymatic method.

The fluorimetric method of Renzini and Valori, utilizing alumina and ion exchange chromatography, was modified to include dl-3H norepinephrine (3H-NE) for individual plasma NE recoveries and mercaptoethanol as a stabilizing agent for the fluorescent lutines. Plasma NE and epinephrine (E) were measured in hypertensive patients, and results were compared with those of the enzymatic method of Engelman in duplicate plasma specimens. The correlations of the NE and the total plasma catecholamine concentrations determined by the two methods were both r = 0.98 (p less than 0.001) and that of the E concentrations was r = 0.79 (p less than 0.01). The reproducibility of the method for measuring 10 ml. aliquots of pooled plasma yielded a standard deviation of less than 10 per cent of the mean. The fluorimetric method was more economical, less time-consuming, and as reliable as the enzymatic method for quantitating plasma catecholamines.

Epinephrine↗