Home About us Contact
|
Home About us Contact | ||
|
|
||
Distinct Spatial (distinct + spatial)
Selected AbstractsGenes involved in the RNA interference pathway are differentially expressed during sea urchin developmentDEVELOPMENTAL DYNAMICS, Issue 11 2007Jia L. Song Abstract RNA-mediated interference (RNAi) is a conserved gene silencing mechanism that involves double-stranded RNA as a signal to trigger the sequence-specific degradation of target mRNA, resulting in posttranscriptional silencing and/or translational repression. Bioinformatic searches in the sea urchin genome database identified homologs of Drosha, DGCR5, Dicer, TRBP, Exportin-5, and Argonautes. Quantitative, real-time polymerase chain reaction indicated that all mRNA accumulate in eggs and in variable levels throughout early development. Whole-mount in situ RNA hybridization showed that all of the important players of the RNAi silencing pathway have abundant mRNA accumulation in oocytes and eggs, but have distinct spatial and temporal expression patterns throughout development. Sequence analysis revealed that each of the four Argonautes examined contain conserved residues important for RNAseH activity within the Piwi domain. This study elucidated that genes involved in the RNAi silencing pathway have dynamic expression and, thus, may have regulatory roles during germ cell development and embryogenesis. Developmental Dynamics 236:3180,3190, 2007. © 2007 Wiley-Liss, Inc. [source] Differential expression of Na,K-ATPase , and , subunit genes in the developing zebrafish inner earDEVELOPMENTAL DYNAMICS, Issue 3 2003Brian Blasiole Abstract We have used whole-mount in situ hybridization to analyze Na,K-ATPase , and , subunit gene expression in the developing zebrafish ear. Four ,1-like (,1a.1, ,1a.2, ,1a.4, and ,1a.5) and two , (,1a and ,2b) subunit genes are expressed in ear beginning at mid-somitogenesis. Each gene exhibits a distinct spatial and temporal expression pattern. The ,1a.1 gene was ubiquitously expressed in the otic epithelium from mid-somitogenesis to 24 hr postfertilization (hpf). Expression of this gene was gradually reduced and by 48 hpf, ,1a.1 transcripts were no longer detectable in the ear. The ,1a.2 and ,1a.5 genes were expressed in regions that correspond to the anterior macula, lateral crista, and semicircular canal projections up to 48 hpf. At later stages, expression of these genes was limited to cells in the dorsolateral septum and semicircular canal projections. ,1a.4 and ,1a transcripts were ubiquitously expressed during ear development and were present in most otic tissues at 5 days postfertilization (dpf). Expression of the ,2b gene, on the other hand, was restricted to subsets of cells that form sensory epithelia. These results strongly suggest different functional roles for individual Na,K-ATPase genes in zebrafish ear development. Na,K-ATPase genes are likely to represent useful markers for the analysis of zebrafish otogenesis. Development Dynamics, 2003. © 2003 Wiley-Liss, Inc. [source] Distinct expression of C1q-like family mRNAs in mouse brain and biochemical characterization of their encoded proteinsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 9 2010Takatoshi Iijima Abstract Many members of the C1q family, including complement C1q and adiponectin, and the structurally related tumor necrosis factor family are secreted and play crucial roles in intercellular signaling. Among them, the Cbln (precerebellin) and C1q-like (C1ql) subfamilies are highly and predominantly expressed in the central nervous system. Although the Cbln subfamily serve as essential trans-neuronal regulators of synaptic integrity in the cerebellum, the functions of the C1ql subfamily (C1ql1,C1ql4) remain unexplored. Here, we investigated the gene expression of the C1ql subfamily in the adult and developing mouse brain by reverse transcriptase-polymerase chain reaction and high-resolution in-situ hybridization. In the adult brain, C1ql1,C1ql3 mRNAs were mainly expressed in neurons but weak expression was seen in glia-like structures in the adult brain. The C1ql1 mRNA was predominantly expressed in the inferior olive, whereas the C1ql2 and C1ql3 mRNAs were strongly coexpressed in the dentate gyrus. Although the C1ql1 and C1ql3 mRNAs were detectable as early as embryonic day 13, the C1ql2 mRNA was observed at later embryonic stages. The C1ql1 mRNA was also expressed transiently in the external granular layer of the cerebellum. Biochemical characterization in heterologous cells revealed that all of the C1ql subfamily proteins were secreted and they formed both homomeric and heteromeric complexes. They also formed hexameric and higher-order complexes via their N-terminal cysteine residues. These results suggest that, like Cbln, the C1ql subfamily has distinct spatial and temporal expression patterns and may play diverse roles by forming homomeric and heteromeric complexes in the central nervous system. [source] Characterization of a transneuronal cytokine family Cbln , regulation of secretion by heteromeric assemblyEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 4 2007Takatoshi Iijima Abstract Cbln1, a member of the C1q and tumor necrosis factor superfamily, plays crucial roles as a cerebellar granule cell-derived transneuronal regulator of synapse integrity and plasticity in Purkinje cells. Although other Cbln family members, Cbln2,Cbln4, have distinct spatial and temporal patterns of expression throughout the CNS, their biochemical and biological properties have remained largely uncharacterized. Here, we demonstrated that in mammalian heterologous cells, Cbln2 and Cbln4 were secreted as N-linked glycoproteins, like Cbln1. In contrast, despite the presence of a functional signal sequence, Cbln3 was not secreted when expressed alone but was retained in the endoplasmic reticulum (ER) or cis -Golgi because of its N-terminal domain. All members of the Cbln family formed not only homomeric but also heteromeric complexes with each other in vitro. Accordingly, when Cbln1 and Cbln3 were co-expressed in heterologous cells, a proportion of the Cbln1 proteins was retained in the ER or cis -Golgi; conversely, some Cbln3 proteins were secreted together with Cbln1. Similarly, in wild-type granule cells expressing Cbln1 and Cbln3, Cbln3 proteins were partially secreted and reached postsynaptic sites on Purkinje cell dendrites, while Cbln3 was almost completely degraded in cbln1 -null granule cells. These results indicate that like Cbln1, Cbln2 and Cbln4 may also serve as transneuronal regulators of synaptic functions in various brain regions. Furthermore, heteromer formation between Cbln1 and Cbln3 in cerebellar granule cells may modulate each other's trafficking and signaling pathways; similarly, heteromerization of other Cbln family proteins may also have biological significance in other neurons. [source] Patterns and consequences of vertebrate Emx gene duplicationsEVOLUTION AND DEVELOPMENT, Issue 4 2009Elizabeth M. Tank SUMMARY We have cloned and analyzed two Emx genes from the lamprey Petromyzon marinus and our findings provide insight into the patterns and developmental consequences of gene duplications during early vertebrate evolution. The Emx gene family presents an excellent case for addressing these issues as gnathostome vertebrates possess two or three Emx paralogs that are highly pleiotropic, functioning in or being expressed during the development of several vertebrate synapomorphies. Lampreys are the most primitive extant vertebrates and characterization of their development and genomic organization is critical for understanding vertebrate origins. We identified two Emx genes from P. marinus and analyzed their phylogeny and their embryological expression relative to other chordate Emx genes. Our phylogenetic analysis shows that the two lamprey Emx genes group independently from the gnathostome Emx1, Emx2, and Emx3 paralogy groups. Our expression analysis shows that the two lamprey Emx genes are expressed in distinct spatial and temporal patterns that together broadly encompass the combined sites of expression of all gnathostome Emx genes. Our data support a model wherein large-scale regulatory evolution of a single Emx gene occurred after the protochordate/vertebrate divergence, but before the vertebrate radiation. Both the lamprey and gnathostome lineages then underwent independent gene duplications followed by extensive paralog subfunctionalization. Emx subfunctionalization in the telencephalon is remarkably convergent and refines our understanding of lamprey forebrain patterning. We also identify lamprey-specific sites of expression that indicate either neofunctionalization in lampreys or sites-specific nonfunctionalization of all gnathostome Emx genes. Overall, we see only very limited correlation between Emx gene duplications and the acquisition of novel expression domains. [source] Dynamic, 3D-Pattern Formation Within Enzyme-Responsive HydrogelsADVANCED MATERIALS, Issue 41 2009Karin S. Straley Dynamic, 3D hydrogel patterns emerge over time in response to cell-secreted enzymes (see image). Composite hydrogels fabricated from engineered proteins exhibit customized half-lives ranging across two orders of magnitude due to slight changes in the primary amino acid sequence. The evolution of internal 3D void structures within these polymeric materials is used to release multiple payload molecules with distinct spatial and temporal delivery profiles. [source] Two tomato ,-expansins show distinct spatial and temporal expression patterns during development of nematode-induced syncytiaPHYSIOLOGIA PLANTARUM, Issue 3 2008Sylwia Fudali Cyst nematodes induce specific syncytial feeding structures within the root which develop from an initial cell by successive incorporation of neighbouring cells through local cell wall dissolutions followed by hypertrophy of included cells. Expansins are known to induce cell wall relaxation and extension in acidic pH, and they are involved in many processes requiring wall modification from cell expansion to cell wall disassembly. We studied the expression pattern of tomato (Lycopersicon esculentum L., cv. Money Maker) expansins during development of syncytia induced by the potato cyst nematode (Globodera rostochiensis Woll.). Based on semi-quantitative reverse transcription,polymerase chain reaction, two expansin genes, LeEXPA4 and LeEXPA5, were selected for detailed examinations because their expression was either elevated in infected roots (LeEXPA4) or specifically induced in the root upon nematode infection (LeEXPA5). Both genes have distinct spatial and temporal expression patterns that may reflect their different roles in syncytium development. LeEXPA4 transcripts were localized predominantly in parenchymatous vascular cylinder cells surrounding syncytia. This finding suggests that LeEXPA4 might be involved in cell wall disassembly or relaxation, mediating syncytium expansion and/or development of conductive tissues. By contrast, LeEXPA5 transcripts were localized in enlarging syncytial elements. Similarly, in immunogold localization experiments, polyclonal antibodies localized the LeEXPA5 protein in cell walls of syncytial elements. This expression pattern suggests that LeEXPA5 gene is specifically involved in enlargement of cells incorporated into syncytium. [source] Synoptic scale wave breaking and its potential to drive NAO-like circulation dipoles: A simplified GCM approachTHE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 638 2009Torben Kunz Abstract Recent studies suggest a synoptic view of the North Atlantic oscillation (NAO) with its positive (negative) phase being the remnant of anticyclonic (cyclonic) synoptic scale wave breaking. This study examines the potential of anticyclonic (AB) and cyclonic wave breaking (CB) to drive NAO-like meridional circulation dipoles by investigating the synoptic evolution of AB and CB events in a mid-latitude eddy-driven jet in a simplified GCM with zonally uniform basic state. First, a method for the detection of such events from daily isentropic maps of potential vorticity and horizontal deformation is constructed. Then, from the obtained sample of events AB- and CB-composites of the upper and lower tropospheric flow are computed, and a distinct spatial and temporal asymmetry in the response to AB and CB events is found. While from the interaction of two AB events (with a mean lifetime of 2.6 days) a strong and short-lived positive phase NAO-like dipole is produced at the surface but not at upper levels, single CB events (4.3 days) are found to drive a strong and more persistent negative phase NAO-like dipole at upper levels but not at the surface. It is concluded that AB (CB) is not capable of driving a positive (negative) phase NAO-like dipole individually. However, the results suggest that equivalent barotropic NAO-like variability may arise from the successive occurrence of AB and CB events. Further, a sensitivity to the strength of the stratospheric polar vortex is found with more (less) frequent AB (CB) events under strong vortex conditions. Copyright © 2009 Royal Meteorological Society [source] | ||||||||||