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Multiple Complexes (multiple + complex)

Distribution by Scientific Domains

Life Sciences	50%
Chemistry	50%

Selected Abstracts

Differential expression of polycomb repression complex 1 (PRC1) members in the developing mouse brain reveals multiple complexes

DEVELOPMENTAL DYNAMICS, Issue 9 2006
Tanja Vogel
Abstract Polycomb group (PcG) genes are regulators of body segmentation and cell growth, therefore being important players during development. PcG proteins form large complexes (PRC) that fulfil mostly repressive regulative functions on homeotic gene expression. Although expression of PcG genes in the brain has been noticed, the involvement of PcG genes in the processes of brain development is not understood. In this study, we analysed the expression patterns of PRC1 complex members to reveal PcG proteins that might be relevant for mouse brain development. Using in situ hybridisation, we show PRC1 activity in proliferative progenitor cells during neurogenesis, but also in maturated neuronal structures. PRC1 complex compositions vary in a spatial and temporal controlled manner during mouse brain development, providing cellular tools to act in different developmental contexts of cell proliferation, cell fate determination, and differentiation. Developmental Dynamics 235:2574,2585, 2006. © 2006 Wiley-Liss, Inc. [source]

Measurement of dissociation rate of biomolecular complexes using CE

ELECTROPHORESIS, Issue 3 2009
Peilin Yang
Abstract Fluorescence anisotropy (FA), non-equilibrium CE of equilibrium mixtures (NECEEM) and high-speed CE were evaluated for measuring dissociation kinetics of peptide,protein binding systems. Fyn-SH3-SH2, a protein construct consisting of the src homology 2 (SH2) and 3 (SH3) domain of the protein Fyn, and a fluorescein-labeled phosphopeptide were used as a model system. All three methods gave comparable half-life of,53,s for Fyn-SH3-SH2:peptide complex. Achieving satisfactory results by NECEEM required columns over 30,cm long. When using Fyn-SH2-SH3 tagged with glutathione S -transferase (GST) as the binding protein, both FA and NECEEM assays gave evidence of two complexes forming with the peptide, yet neither method allowed accurate measurement of dissociation rates for both complexes because of a lack of resolution. High-speed CE, with a 7,s separation time, enabled separation of both complexes and allowed determination of dissociation rate of both complexes independently. The two complexes had half-lives of 22.0±2.7 and 58.8±6.1,s, respectively. Concentration studies revealed that the GST-Fyn-SH3-SH2 protein formed a dimer so that complexes had binding ratios of 2:1 (protein-to-peptide ratio) and 2:2. Our results demonstrate that although all methods are suitable for 1:1 binding systems, high-speed CE is unique in allowing multiple complexes to be resolved simultaneously. This property allows determination of binding kinetics of complicated systems and makes the technique useful for discovering novel affinity interactions. [source]

Alu-DNA repeat-binding protein p68 is a part of Alu-RNA containing ,-RNP

FEBS JOURNAL, Issue 8 2000
Dmitry V. Lukyanov
An Alu-DNA repeat-binding protein with a molecular mass of 68 kDa (p68) is identified in the somatic human cell nucleoplasm. Gel mobility shift assay (GMSA), South-western blotting and affinity purification on DNA attached to the carrier were used in the identification. GMSA revealed multiple complexes with the exponential dependence of their relative mobility. A narrow binding site of the p68 was revealed using synthetic oligonucleotides. It is located between the A-box and B-box of the RNA polymerase III promoter and is identical to that reported for the Alu-binding protein from human spermatozoids. The same narrow binding site, the similarity of the isolation procedure from germ and somatic cells, and similar binding properties and molecular masses suggest homology of the two proteins. Antibodies raised against Alu-protein complexes led to hypershift of the complexes in GMSA and stained p68 in active fractions in human spermatozoids and in Alu-RNA-containing ,-RNP particles. Immunofluorescence of a HeLa cell monolayer revealed an intranuclear dot pattern with the dots corresponding to euchromatin areas and some dots located at the cell periphery in the cytoplasm. ,-RNP particles bound Alu-DNA in vitro and contained p68 as shown using the immunogold procedure. Alu-DNA binding activity was revealed in cytoplasm as well as in nucleoplasm. The possible nature of the main Alu-DNA binding protein and its involvement in the particle structure are discussed. [source]

Mass spectrometry study of hemoglobin-oxaliplatin complexes in colorectal cancer patients and potential association with chemotherapeutic responses

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 17 2006
Rupasri Mandal
Oxaliplatin is the most active platinum (Pt)-containing anticancer drug for the treatment of advanced colorectal cancer. We report here the study of potential association of the levels of oxaliplatin-protein complexes in 19 cancer patients with treatment efficacy using size-exclusion high-performance liquid chromatography with inductively coupled plasma mass spectrometry (HPLC/ICPMS) and nanoelectrospray ionization mass spectrometry (nanoESI-MS) techniques. Blood samples from 19 colorectal cancer patients were collected at 1 and 48,h after the first infusion of oxaliplatin. HPLC/ICPMS quantification of the oxaliplatin-protein complexes showed that the levels of Pt-protein complexes in plasma samples at 48,h were reduced by approximately 50% compared to those at 1,h, whereas those in hemolysates did not change significantly. The concentrations of hemoglobin (Hb)-oxaliplatin complexes determined by HPLC/ICPMS ranged from 3.1 to 8.7,µM. NanoESI-MS analysis of the patient hemolysates showed three distinct mass spectral profiles of the Hb-oxaliplatin complexes: (1) 1:1, (2) 1:1 with 1:2, and (3) multiple complexes of 1:1, 1:2, 1:3, and 1:4, corresponding to the Hb-oxaliplatin complex concentrations determined by HPLC/ICPMS. Potential association of variables including Hb-oxaliplatin complex concentrations with time to progress as the treatment efficacy indicator was analyzed using the Cox model. Multivariate analysis of the potential predictors showed that the statistically significant variables were Hb-oxaliplatin complex concentration (p,=,0.02), performance status (p,=,0.02), baseline neutrophil count (p,=,0.05), and the site of the primary cancer (colon vs. rectal, p,=,0.01). The hazard ratio for the concentration of the Hb-oxaliplatin complexes was 2.4, suggesting that the risk of cancer progression significantly increased with increasing of Hb-oxaliplatin complexes in patients. These results demonstrate that the level of the Hb-oxaliplatin complexes in erythrocytes is a potential biomarker for indicating inter-patient variations in oxaliplatin treatment efficacy. Copyright © 2006 John Wiley & Sons, Ltd. [source]