Life Sciences Commons^™

Concise Review: Dendritic Cell Development In The Context Of The Spleen Microenvironment, Jonathan Tan, Helen O'Neill

Jonathan Tan

The dendritic cell (DC) population in spleen comprises a mixture of cells including endogenous DC progenitors, DC precursors migrating in from blood and bone marrow, and DC in different states of differentiation and activation. A role for different microenvironments in supporting the dynamic development of murine DC of different types or lineages is considered here. Recent evidence for production of DC dependent on splenic stromal cells is reviewed in the light of evidence that cell production is dependent on cells comprising an endothelial niche in spleen. The possibility that self-renewing progenitors in spleen give rise to DC with tolerogenic or …

Tailed Forisomes Of Canavalia Gladiata: A New Model To Study Ca2+-Driven Protein Contractility, Winfried Peters, Michael Knoblauch, Stephen Warmann, Reinhard Schnetter, Amy Shen, William Pickard

Winfried S. Peters

The Regulation Of Genes And Genomes By Small Rnas., Victor Ambros, Xuemei Chen

Victor R. Ambros

A recent Keystone Symposium on 'MicroRNAs and siRNAs: Biological Functions and Mechanisms' was organized by David Bartel and Shiv Grewal (and was held in conjunction with 'RNAi for Target Validation and as a Therapeutic', organized by Stephen Friend and John Maraganore). The 'MicroRNAs and siRNAs' meeting brought together scientists working on diverse biological aspects of small regulatory RNAs, including microRNAs, small interfering RNAs (siRNAs) and Piwi-interacting RNAs (piRNAs and rasiRNAs). Among the themes discussed were the diversity of small regulatory RNAs and their developmental functions, their biogenesis, the identification of their regulatory targets, their mechanisms of action, and their roles …

Reversible Birefringence Suggests A Role For Molecular Self-Assembly In Forisome Contractility, Winfried Peters, Reinhard Schnetter, Michael Knoblauch

Winfried S. Peters

Potent Effect Of Target Structure On Microrna Function, Peter Williams, Dang Long, Rosalind Lee, Chi Chan, Victor Ambros, Ye Ding

Victor R. Ambros

MicroRNAs (miRNAs) are small noncoding RNAs that repress protein synthesis by binding to target messenger RNAs. We investigated the effect of target secondary structure on the efficacy of repression by miRNAs. Using structures predicted by the Sfold program, we model the interaction between an miRNA and a target as a two-step hybridization reaction: nucleation at an accessible target site followed by hybrid elongation to disrupt local target secondary structure and form the complete miRNA-target duplex. This model accurately accounts for the sensitivity to repression by let-7 of various mutant forms of the Caenorhabditis elegans lin-41 3' untranslated region and for …

Characterization Of Microrna Expression Levels And Their Biological Correlates In Human Cancer Cell Lines., Caifu Chen, Arti Gaur, David Jewell, Yu Liang, Dana Ridzon, Jason Moore, Victor Ambros, Mark Israel

Victor R. Ambros

MicroRNAs are small noncoding RNAs that function by regulating target gene expression posttranscriptionally. They play a critical role in developmental and physiologic processes and are implicated in the pathogenesis of several human diseases including cancer. We examined the expression profiles of 241 human microRNAs in normal tissues and the NCI-60 panel of human tumor-derived cell lines. To quantify microRNA expression, we employed a highly sensitive technique that uses stem-loop primers for reverse transcription followed by real-time PCR. Most microRNAs were expressed at lower levels in tumor-derived cell lines compared with the corresponding normal tissue. Agglomerative hierarchical clustering analysis of microRNA …

The 2007 George W. Beadle Medal. Robert K. Herman., Victor Ambros

Victor R. Ambros

No abstract provided.

Runx2 Is Essential For Larval Hyobranchial Cartilage Formation In Xenopus Laevis, Ryan Kerney, Joshua Gross, James Hanken

Ryan Kerney

The vertebrate transcription factor protein Runx2 is regarded as a “master regulator” of bone formation due to the dramatic loss of the osseous skeleton in the mouse homozygous knockout. However, Runx2 mRNA also is expressed in the pre-hypertrophic cartilaginous skeleton of the mouse and chicken, where its developmental function is largely unknown. Several tiers of Runx2 regulation exist in the mouse, any of which may account for its seeming biological inactivity during early stages of skeletogenesis. Unlike mouse and chicken, zebrafish require Runx2 function in early cartilage differentiation. The present study reveals that the earlier functional role of Runx2 in …

Concise Review: Dendritic Cell Development In The Context Of The Spleen Microenvironment, Jonathan Tan, Helen O'Neill

Helen O'Neill

The dendritic cell (DC) population in spleen comprises a mixture of cells including endogenous DC progenitors, DC precursors migrating in from blood and bone marrow, and DC in different states of differentiation and activation. A role for different microenvironments in supporting the dynamic development of murine DC of different types or lineages is considered here. Recent evidence for production of DC dependent on splenic stromal cells is reviewed in the light of evidence that cell production is dependent on cells comprising an endothelial niche in spleen. The possibility that self-renewing progenitors in spleen give rise to DC with tolerogenic or …

Use Of Gene Profiling To Describe A Niche For Dendritic Cell Development, Geneviève Despars, Terence O'Neill, Helen O'Neill

Helen O'Neill

Gene profiling provides a multitude of data on individual gene expression. The view is expressed here that unreplicated data can be used in a descriptive way to compare cell populations in terms of their lineage characteristics and function. In these studies, the aim is to provide a snapshot of gene expression or its absence as a reflection of cell lineage or type, rather than gain a reliable expression measure for all genes expressed. The data set used in this analysis represents gene expression in the splenic stroma STX3 supportive of dendritic cell hematopoiesis and the lymph node stroma 2RL22, which …