84 research outputs found
Complete diagrammatics of the single ring theorem
Using diagrammatic techniques, we provide explicit functional relations
between the cumulant generating functions for the biunitarily invariant
ensembles in the limit of large size of matrices. The formalism allows to map
two distinct areas of free random variables: Hermitian positive definite
operators and non-normal R-diagonal operators. We also rederive the
Haagerup-Larsen theorem and show how its recent extension to the eigenvector
correlation function appears naturally within this approach.Comment: 18 pages, 6 figures, version accepted for publicatio
Nuclear Import and Export Signals of Human Cohesins SA1/STAG1 and SA2/STAG2 Expressed in Saccharomyces cerevisiae
Abstract
Background: Human SA/STAG proteins, homologues of the yeast Irr1/Scc3 cohesin, are the least studied constituents of the
sister chromatid cohesion complex crucial for proper chromosome segregation. The two SA paralogues, SA1 and SA2, show
some specificity towards the chromosome region they stabilize, and SA2, but not SA1, has been shown to participate in
transcriptional regulation as well. The molecular basis of this functional divergence is unknown.
Methodology/Principal Findings: In silico analysis indicates numerous putative nuclear localization (NLS) and export (NES)
signals in the SA proteins, suggesting the possibility of their nucleocytoplasmic shuttling. We studied the functionality of
those putative signals by expressing fluorescently tagged SA1 and SA2 in the yeast Saccharomyces cerevisiae. Only the Nterminal
NLS turned out to be functional in SA1. In contrast, the SA2 protein has at least two functional NLS and also two
functional NES. Depending on the balance between these opposing signals, SA2 resides in the nucleus or is distributed
throughout the cell. Validation of the above conclusions in HeLa cells confirmed that the same N-terminal NLS of SA1 is
functional in those cells. In contrast, in SA2 the principal NLS functioning in HeLa cells is different from that identified in
yeast and is localized to the C-terminus.
Conclusions/Significance: This is the first demonstration of the possibility of non-nuclear localization of an SA protein. The
reported difference in the organization between the two SA homologues may also be relevant to their partially divergent
functions. The mechanisms determining subcellular localization of cohesins are only partially conserved between yeast and
human cells
Identificação e caracterização de espécies de Colletotrichum associadas à antracnose de anonåceas no estado de Alagoas
Cytochrome P450 mRNA expressions along with in vitro differentiation of hepatocyte precursor cells from fetal, young and old rats.
PARP-1 and YY1 Are Important Novel Regulators of CXCL12 Gene Transcription in Rat Pancreatic Beta Cells
Despite significant progress, the molecular mechanisms responsible for pancreatic beta cell depletion and development of diabetes remain poorly defined. At present, there is no preventive measure against diabetes. The positive impact of CXCL12 expression on the pancreatic beta cell prosurvival phenotype initiated this study. Our aim was to provide novel insight into the regulation of rat CXCL12 gene (Cxcl12) transcription. The roles of poly(ADP-ribose) polymerase-1 (PARP-1) and transcription factor Yin Yang 1 (YY1) in Cxcl12 transcription were studied by examining their in vitro and in vivo binding affinities for the Cxcl12 promoter in a pancreatic beta cell line by the electrophoretic mobility shift assay and chromatin immunoprecipitation. The regulatory activities of PARP-1 and YY1 were assessed in transfection experiments using a reporter vector with a Cxcl12 promoter sequence driving luciferase gene expression. Experimental evidence for PARP-1 and YY1 revealed their trans-acting potential, wherein PARP-1 displayed an inhibitory, and YY1 a strong activating effect on Cxcl12 transcription. Streptozotocin (STZ)-induced general toxicity in pancreatic beta cells was followed by changes in Cxcl12 promoter regulation. PARP-1 binding to the Cxcl12 promoter during basal and in STZ-compromised conditions led us to conclude that PARP-1 regulates constitutive Cxcl12 expression. During the early stage of oxidative stress, YY1 exhibited less affinity toward the Cxcl12 promoter while PARP-1 displayed strong binding. These interactions were accompanied by Cxcl12 downregulation. In the later stages of oxidative stress and intensive pancreatic beta cell injury, YY1 was highly expressed and firmly bound to Cxcl12 promoter in contrast to PARP-1. These interactions resulted in higher Cxcl12 expression. The observed ability of PARP-1 to downregulate, and of YY1 to upregulate Cxcl12 promoter activity anticipates corresponding effects in the natural context where the functional interplay of these proteins could finely balance Cxcl12 transcription
Reliability of molecular host-identification methods for ticks: an experimental in vitro study with Ixodes ricinus
Gut contents, digestive half-lives and feeding state prediction in the soil predatory mite Pergamasus longicornis (Mesostigmata: Parasitidae)
Controlled Template-Assisted Assembly of Plasmid DNA into Nanometric Particles with High DNA Concentration
- âŠ