1,720,982 research outputs found
Synthesis of Formacetal‐Linked Dinucleotides to Facilitate dsDNA Bending and Binding to the Homeodomain of Pax6
No full textTwo formacetal-linked dinucleotides TT and TT were synthesized as phosphoramidite building blocks for solid-phase synthesis. Incorporated in a 29-mer DNA, the oligomers P3(TT) and P3(TA) were studied with respect to the binding activity towards the Pax6 homeodomain. Substitution of the negatively charged phosphodiester by a neutral formacetal linker facilitates the bent conformation of double-stranded DNA. The duplex stability was affected more significantly by the TT formacetal modification, whereas destabilization induced by TA was less pronounced. Based on CD spectroscopy, the TA formacetal-modified oligomer P3(TA) A has mainly B-DNA topology, whereas the P3(TT) modified oligomet significantly deviated from B-form DNA. The binding affinity of the P3 oligomer towards Pax6 HD was investigated by in vitro EMSA experiments providing even a small increase in binding affinity for the P3(TA) T oligomer. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Different expression of the catalytic alpha subunits of the AMP activated protein kinase - an immunohistochemical study in human tissue
No full textAMPK is an ubiquitously distributed multienzyme complex. It is an important energy sensor and regulator of cellular metabolic activity. In this study we analyzed for the first time the cellular distribution of the catalytically active subunits AMPK alpha 1 and alpha 2 in different human tissues by immunohistochemistry. We found different expression patterns for both isoforms. AMPK alpha 2 expression clearly dominates in skeletal myocytes and cardiomyocytes, whereas AMPK alpha 1 dominates in a number of secreting cells, like mammary glands, islets of langerhans and cells of the colon crypts.Deutsche Diabetes Gesellschaft (DDG
Cathepsin D Deficiency Is Associated with a Human Neurodegenerative Disorder
No full textCathepsin D is a ubiquitously expressed lysosomal protease that is involved in proteolytic degradation, cell invasion, and apoptosis. In mice and sheep, cathepsin D deficiency is known to cause a fatal neurodegenerative disease. Here, we report a novel disorder in a child with early blindness and progressive psychomotor disability. Two missense mutations in the CTSD gene, F229I and W383C, were identified and were found to cause markedly reduced proteolytic activity and a diminished amount of cathepsin D in patient fibroblasts. Expression of cathepsin D mutants in cathepsin D−/− mouse fibroblasts revealed disturbed posttranslational processing and intracellular targeting for W383C and diminished maximal enzyme velocity for F229I. The structural effects of cathepsin D mutants were estimated by computer modeling, which suggested larger structural alterations for W383C than for F229I. Our studies broaden the group of human neurodegenerative disorders and add new insight into the cellular functions of human cathepsin D
The structure of tripeptidyl peptidase I (TPP1) provides insight into the molecular basis of late infantile neuronal ceroid lipofuscinosis
No full textDifferent expression of the catalytic alpha subunits of the AMP activated protein kinase - an immunohistochemical study in human tissue
No full textAMPK is an ubiquitously distributed multienzyme complex. It is an important energy sensor and regulator of cellular metabolic activity. In this study we analyzed for the first time the cellular distribution of the catalytically active subunits AMPK alpha 1 and alpha 2 in different human tissues by immunohistochemistry. We found different expression patterns for both isoforms. AMPK alpha 2 expression clearly dominates in skeletal myocytes and cardiomyocytes, whereas AMPK alpha 1 dominates in a number of secreting cells, like mammary glands, islets of langerhans and cells of the colon crypts.Deutsche Diabetes Gesellschaft (DDG
Establishment of an insect cell expression system for rat Abcb6, an ATP-binding cassette transporter involved in copper tolerance
No full textThe homeodomain of PAX6 is essential for PAX6-dependent activation of the rat glucagon gene promoter: Evidence for a PH0-like binding that induces an active conformation
No full textThe transcription factor PAX6 plays an important role in transcriptional regulation of the peptide hormone glucagon from pancreatic alpha-cells. PAX6 contains two DNA binding domains, the paired domain (PD) and the homeodomain (HD). While the interaction of the PD with the PAX6 responsive elements G1 and G3 in the rat glucagon gene promoter is well understood, the role of the PAX6 HD for PAX6 binding and function on G1 and G3 remains unclear. In EMSA studies the PAX6 HD was found to be mandatory for PAX6 binding to G1 but not to G3. Transient transfections with luciferase reporter gene constructs revealed the HD to be critical for proper function of PAX6 on both, G1 and G3. Transfection data with variant promoter constructs and limited proteolysis assays demonstrated that the DNA sequence located 5' to the PD binding site plays an important role for PAX6 function and its conformation on the elements G1 and G3. Taken together, our data indicate a PH0-like binding of PAX6 to the glucagon promoter elements G1 and G3 where the HD binding site is abutted directly to the PD binding motif The data suggest that the PH0-like binding induces a transcriptionally active conformation of PAX6. (C) 2009 Elsevier B.V. All rights reserved.Deutsche Forschungsgemeinschaft [SFB402/A3
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