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Complex Members (complex + member)
Selected AbstractsTaming the fierce roller: an "enhanced" understanding of cellular differentiation in VolvoxBIOESSAYS, Issue 1 2002Stephen M. Miller Few organisms offer a better opportunity to explore the mechanisms of cellular differentiation, and their origins, than Volvox. Volvox consists of just two cell types, germ and soma, and is the most complex member of a family of green algae that includes unicellular and multicellular relatives. At the heart of the cell-fate determination program of Volvox carteri is the regA gene, which encodes a putative transcriptional repressor that prevents somatic cells from expressing reproductive functions. Stark et al.(1) have dissected the regA gene to determine how its expression is restricted to somatic cells. Their results suggest that regA expression is controlled by multiple enhancers, the most important of which prevents transcription in reproductive cells. While these findings shed light on Volvox development, they also raise a new set of questions about the mechanisms that control the germ,soma dichotomy in this organism. BioEssays 24:3,7, 2002. © 2002 John Wiley & Sons, Inc. [source] Differential expression of polycomb repression complex 1 (PRC1) members in the developing mouse brain reveals multiple complexesDEVELOPMENTAL DYNAMICS, Issue 9 2006Tanja 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] Cover Picture: Electrophoresis 4/2008ELECTROPHORESIS, Issue 4 2008Article first published online: 22 FEB 200 This special issue on capillary electrochromatography (CEC) and electrokinetic capillary chromatography (EKC) provides the reader with the latest developments and improvements in these two closely related micro-column separation techniques. Issue 4 also offers one Fast Track article describing particularly important investigations in electrophoresis: Identification of unknown protein complex members by radiolocalization and analysis of low-abundance complexes resolved using native polyacrylamide gel electrophoresis Mahuya Bose, Brian P. Adams, Randy M. Whittal, Himangshu S. Bose [source] Presenilin function and ,-secretase activityJOURNAL OF NEUROCHEMISTRY, Issue 4 2005A. L. Brunkan Abstract Alzheimer's disease (AD) is the most common form of dementia and is characterized pathologically by the accumulation of ,-amyloid (A,) plaques and neurofibrillary tangles in the brain. Genetic studies of AD first highlighted the importance of the presenilins (PS). Subsequent functional studies have demonstrated that PS form the catalytic subunit of the ,-secretase complex that produces the A, peptide, confirming the central role of PS in AD biology. Here, we review the studies that have characterized PS function in the ,-secretase complex in Caenorhabditis elegans, mice and in in vitro cell culture systems, including studies of PS structure, PS interactions with substrates and other ,-secretase complex members, and the evidence supporting the hypothesis that PS are aspartyl proteases that are active in intramembranous proteolysis. A thorough knowledge of the mechanism of PS cleavage in the context of the ,-secretase complex will further our understanding of the molecular mechanisms that cause AD, and may allow the development of therapeutics that can alter A, production and modify the risk for AD. [source] Molecular phylogenetic analysis of Leibnitzia Cass. (Asteraceae: Mutisieae: Gerbera -complex), an Asian,North American disjunct genusJOURNAL OF SYSTEMATICS EVOLUTION, Issue 3 2010Kristen E. BAIRD Abstract Leibnitzia comprises six species of perennial herbs that are adapted to high elevation conditions and is one of only two Asteraceae genera known to have an exclusively disjunct distribution spanning central to eastern Asia and North America. Molecular phylogenetic analysis of Leibnitzia and other Gerbera -complex members indicates that Leibnitzia is monophyletic, which is in contrast with our expectation that the American Leibnitzia species L. lyrata and L. occimadrensis would be more closely related to another American member of the Gerbera -complex, namely Chaptalia. Ancestral area reconstructions show that the historical biogeography of the Gerbera -complex mirrors that of the entire Asteraceae, with early diverging lineages located in South America that were followed by transfers to Africa and Eurasia and, most recently, to North America. Intercontinental transfer of Leibnitzia appears to have been directed from Asia to North America. Independent calibrations of nuclear (ribosomal DNA internal transcribed spacer region) and chloroplast (trnL,rpl32 intron) DNA sequence data using relaxed clock methods and either mean rate or fossil-based priors unanimously support Miocene and younger divergence times for Gerbera -complex taxa. The ages are not consistent with most Gondwanan vicariance episodes and, thus, the global distribution of Gerbera -complex members must be explained in large part by long-distance dispersal. American species of Leibnitzia are estimated to have diverged from their Asian ancestor during the Quaternary (ca. 2 mya) and either migrated overland to North America via Beringia and retreated southwards along high elevation corridors to their present location in southwestern North America or were dispersed long distance. [source] | ||||||||||