Search results for "Repressor Protein"
showing 10 items of 169 documents
Drosophila Enhancer of Zeste/ESC Complexes Have a Histone H3 Methyltransferase Activity that Marks Chromosomal Polycomb Sites
2002
AbstractEnhancer of Zeste is a Polycomb Group protein essential for the establishment and maintenance of repression of homeotic and other genes. In the early embryo it is found in a complex that includes ESC and is recruited to Polycomb Response Elements. We show that this complex contains a methyltransferase activity that methylates lysine 9 and lysine 27 of histone H3, but the activity is lost when the E(Z) SET domain is mutated. The lysine 9 position is trimethylated and this mark is closely associated with Polycomb binding sites on polytene chromosomes but is also found in centric heterochromatin, chromosome 4, and telomeric sites. Histone H3 methylated in vitro by the E(Z)/ESC complex …
Gene expression of stem cells at different stages of ontological human development.
2013
Abstract Objectives To compare multipotent mesenchymal stem cells (MSCs) obtained from chorionic villi (CV), amniotic fluid (AF) and placenta, with regard to their phenotype and gene expression, in order to understand if MSCs derived from different extra-embryonic tissues, at different stages of human ontological development, present distinct stemness characteristics. Study design MSCs obtained from 30 samples of CV, 30 of AF and 10 placentas (obtained from elective caesarean sections) were compared. MSCs at second confluence cultures were characterized by immunophenotypic analysis with flow cytometry using FACS CANTO II. The expression of the genes Oct-4 (Octamer-binding transcription fact…
Zfp819, a novel KRAB-zinc finger protein, interacts with KAP1 and functions in genomic integrity maintenance of mouse embryonic stem cells
2013
AbstractPluripotency is maintained by both known and unknown transcriptional regulatory networks. In the present study, we have identified Zfp819, a KRAB-zinc finger protein, as a novel pluripotency-related factor and characterized its role in pluripotent stem cells. We show that Zfp819 is expressed highly in various types of pluripotent stem cells but not in their differentiated counterparts. We identified the presence of non-canonical nuclear localization signals in particular zinc finger motifs and identified them as responsible for the nuclear localization of Zfp819. Analysis of the Zfp819 promoter region revealed the presence of a transcriptionally active chromatin signature. Moreover,…
UME6, a Novel Filament-specific Regulator ofCandida albicansHyphal Extension and Virulence
2008
The specific ability of the major human fungal pathogen Candida albicans, as well as many other pathogenic fungi, to extend initial short filaments (germ tubes) into elongated hyphal filaments is important for a variety of virulence-related processes. However, the molecular mechanisms that control hyphal extension have remained poorly understood for many years. We report the identification of a novel C. albicans transcriptional regulator, UME6, which is induced in response to multiple host environmental cues and is specifically important for hyphal extension. Although capable of forming germ tubes, the ume6Δ/ume6Δ mutant exhibits a clear defect in hyphal extension both in vitro and during i…
Pseudohyphal Regulation by the Transcription Factor Rfg1p in Candida albicans
2010
ABSTRACT The opportunistic human fungal pathogen Candida albicans is a major cause of nosocomial infections. One of the fundamental features of C. albicans pathogenesis is the yeast-to-hypha transition. Hypha formation is controlled positively by transcription factors such as Efg1p and Cph1p, which are required for hyphal growth, and negatively by Tup1p, Rfg1p, and Nrg1p. Previous work by our group has shown that modulating NRG1 gene expression, hence altering morphology, is intimately linked to the capacity of C. albicans to cause disease. To further dissect these virulence mechanisms, we employed the same strategy to analyze the role of Rfg1p in filamentation and virulence. Studies using …
Association between human papillomavirus 16 E6 variants and human leukocyte antigen class I polymorphism in cervical cancer of Swedish women.
2003
Abstract Persistent infection with human papillomavirus (HPV), particularly HPV16, represents the prime risk factor in cervical carcinogenesis. HPV variants ( e.g. , within the E6 gene) together with immunogenetic factors of the host may be responsible either for effective viral clearance, or alternatively, for viral persistence. Peripheral blood from 27 HPV16 positive Swedish women with cervical carcinoma, who had previously been tested for HPV16 E6 variants, was used for human leukocyte antigen (HLA) class I typing. Women with HLA-B*44, HLA-B*51, or HLA-B*57 who were infected with the HPV16 E6 variant L83V had an approximately four- to fivefold increased risk for cancer compared with cont…
Dissection of human papillomavirus type 33 L2 domains involved in nuclear domains (ND) 10 homing and reorganization
2003
Abstract We have recently shown that the minor capsid protein L2 of human papillomavirus type 33 (HPV33) recruits the transcriptional repressor Daxx into nuclear domains (ND) 10 and causes the loss of the transcriptional activator Sp100 from these subnuclear structures (Florin et al., 2002b) . In order to dissect L2 domains involved in nuclear translocation, ND10 homing, loss of Sp100, and recruitment of Daxx, a detailed deletion mutagenesis of L2 was performed. Using immunofluorescence and green fluorescent protein fusions, we have identified two nuclear localization signals (NLS) in the central and C-terminal part of L2, respectively, homologous to previously identified NLS in HPV6B L2 (S…
Transcriptional regulation of the proton translocating NADH dehydrogenase genes (nuoA-N) of Escherichia coli by electron acceptors, electron donors a…
1995
The promoter region and transcriptional regulation of the nuoA-N gene locus encoding the proton-translocating NADH:quinone oxidoreductase was analysed. A 560 bp intergenic region upstream of the nuo locus was followed by a gene (designated lrhA for LysR homologue A) coding for a gene regulator similar to those of the LysR family. Disruption of lrhA did not affect growth (respiratory or non-respiratory) or expression of nuo significantly. Transcriptional regulation of nuo by electron acceptors, electron donors and the transcriptional regulators ArcA, FNR, NarL and NarP, and by IHF (integration host factor) was studied with protein and operon fusions containing the promoter region up to base …
Induction of interferon regulatory factors, 2′‐5′ oligoadenylate synthetase, P68 kinase and RNase L in chronic myelogenous leukaemia cells and its re…
1996
The genes crucially determining the therapeutic response of chronic myelogenous leukaemia (CML) to interferon-alpha (IFN-alpha) are unknown. Recently, two independent IFN-alpha signalling pathways were identified: the classic pathway mediates induction of 2'-5' oligoadenylate synthetase (2-5 OAS), p68 kinase and IFN regulatory factor-2 (IRF-2), whereas the alternate pathway leads to activation of IFN regulatory factor-1 (IRF-1). We investigated whether deficient or imbalanced expression of components of these two pathways is associated with resistance of CML cells to antiproliferative action of IFN alpha/beta. Constitutive and IFN-induced transcript levels of IFN-dependent genes in mononucl…
Regulatory O 2 tensions for the synthesis of fermentation products in Escherichia coli and relation to aerobic respiration
1997
In an oxystat, the synthesis of the fermentation products formate, acetate, ethanol, lactate, and succinate of Escherichia coli was studied as a function of the O2 tension (pO2) in the medium. The pO2 values that gave rise to half-maximal synthesis of the products (pO0. 5) were 0.2-0.4 mbar for ethanol, acetate, and succinate, and 1 mbar for formate. The pO0.5 for the expression of the adhE gene encoding alcohol dehydrogenase was approximately 0.8 mbar. Thus, the pO2 for the onset of fermentation was distinctly lower than that for anaerobic respiration (pO0.5/= 5 mbar), which was determined earlier. An essential role for quinol oxidase bd in microaerobic growth was demonstrated. A mutant de…