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Morphogenetic Processes (morphogenetic + process)
Selected AbstractsModularity of the rodent mandible: Integrating bones, muscles, and teethEVOLUTION AND DEVELOPMENT, Issue 6 2008Miriam Leah Zelditch Summary Several models explain how a complex integrated system like the rodent mandible can arise from multiple developmental modules. The models propose various integrating mechanisms, including epigenetic effects of muscles on bones. We test five for their ability to predict correlations found in the individual (symmetric) and fluctuating asymmetric (FA) components of shape variation. We also use exploratory methods to discern patterns unanticipated by any model. Two models fit observed correlation matrices from both components: (1) parts originating in same mesenchymal condensation are integrated, (2) parts developmentally dependent on the same muscle form an integrated complex as do those dependent on teeth. Another fits the correlations observed in FA: each muscle insertion site is an integrated unit. However, no model fits well, and none predicts the complex structure found in the exploratory analyses, best described as a reticulated network. Furthermore, no model predicts the correlation between proximal parts of the condyloid and coronoid, which can exceed the correlations between proximal and distal parts of the same process. Additionally, no model predicts the correlation between molar alveolus and ramus and/or angular process, one of the highest correlations found in the FA component. That correlation contradicts the basic premise of all five developmental models, yet it should be anticipated from the epigenetic effects of mastication, possibly the primary morphogenetic process integrating the jaw coupling forces generated by muscle contraction with those experienced at teeth. [source] Lyonization pattern of normal human nailsGENES TO CELLS, Issue 5 2008Mariko Okada To examine the X-inactivation patterns of normal human nails, we performed the human androgen receptor gene assay of DNA samples extracted separately from each finger and toe nail plates of nine female volunteers. The X-inactivation pattern of each nail was unique and constant for at least 2 years. The frequency of nails with one of the two X-chromosomes exclusively inactivated was 25.9%. In the nails composed of two types of cells with either one X-chromosome inactivated, the two cell types were distributed in patchy mosaics. These findings suggest that the composition of precursor cells of each nail is maintained at each site at least through several cycles of regeneration time, and that the nail plate has a longitudinal band pattern, each band consisting of cells with only one of the two X-chromosomes inactivated. Using the frequency of nails with one of two X-chromosomes exclusively inactivated, we estimated the number of progenitor cells that gave rise to the nail plate during development to be about 3, under the assumption that the process follows the binominal distribution model. A strong correlation observed among the big, index and little fingers, and among the corresponding toes suggests an interesting interpretation concerning their morphogenetic process. [source] Embryonic transcription factors in human breast cancerIUBMB LIFE, Issue 3 2006Karoline J. Briegel Abstract Growing evidence suggests that breast cancer cells often reactivate latent developmental programs in order to efficiently execute the multi-step process of tumorigenesis. This review focuses on key transcriptional regulators of embryonic development that are deregulated in breast cancer and discusses the molecular mechanisms by which these proteins control carcinogenesis. Reminiscent of their function during development, embryonic transcription factors regulate changes in gene expression that promote tumor cell growth, cell survival and motility, as well as a morphogenetic process called epithelial-mesenchymal transition (EMT), which is implicated in both breast metastasis and tumor recurrence. Because of their pivotal roles in breast tumor progression, these factors represent valuable new biomarkers for breast cancer detection as well as promising new targets for anti-invasive drugs. IUBMB Life, 58: 123-132, 2006 [source] Toward understanding the genetic basis of neural tube defectsCLINICAL GENETICS, Issue 4 2007Z Kibar Neural tube defects (NTDs) represent a common group of severe congenital malformations that result from failure of neural tube closure during early development. Their etiology is quite complex involving environmental and genetic factors and their underlying molecular and cellular pathogenic mechanisms remain poorly understood. Animal studies have recently demonstrated an essential role for the planar cell polarity pathway (PCP) in mediating a morphogenetic process called convergent extension during neural tube formation. Alterations in members of this pathway lead to NTDs in vertebrate models, representing novel and exciting candidates for human NTDs. Genetic studies in NTDs have focused mainly on folate-related genes based on the finding that perinatal folic acid supplementation reduces the risk of NTDs by 60,70%. A few variants in these genes have been found to be significantly associated with an increased risk for NTDs. The candidate gene approach investigating genes involved in neurulation has failed to identify major causative genes in the etiology of NTDs. Despite this history of generally negative findings, we are achieving a rapid and impressive progress in understanding the genetic basis of NTDs, based mainly on the powerful tool of animal models. [source] vrille is required to ensure tracheal integrity in Drosophila embryoDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 5 2010Sébastien Szuplewski The Drosophila bZIP transcription factor Vrille (VRI) is required for growth, circadian clock regulation and metamorphosis. We identified here a new facet of vrille (vri) function and show that it is required for tracheal development. We show that, in the embryo, VRI is expressed in a complex and dynamic pattern and is found in amnioserosa, subdomains of the developing gut and in trachea cells. We also show that, as expected, the protein is nuclear. We then asked whether VRI was involved in morphogenetic processes such as gut and tracheal development. We therefore investigated the development of these tissues in vri mutants, and although we did not observe any defects in gut morphology, we identified differentiation defects that affect tracheal integrity. Most of the defects were observed after stage 14 and affect all branches, resulting in branch breaks, abnormal branching and elongation. [source] Development of the endoderm and gut in medaka, Oryzias latipesDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 5 2006Daisuke Kobayashi We performed an extensive analysis of endodermal development and gut tube morphogenesis in the medaka embryo by histology and in situ hybridization. The markers used in these analyses included sox17, sox32, foxA2, gata-4, -5, -6 and shh. sox17, sox32, foxA2, and gata-5 and -6 are expressed in the early endoderm to the onset of gut tube formation. Sections of medaka embryos hybridized with foxA2, a pan-endodermal marker during gut morphogenesis, demonstrated that gut tube formation is initiated in the anterior portion and that the anterior and mid/posterior gut undergo distinct morphogenetic processes. Tube formation in the anterior endoderm that is fated to the pharynx and esophagus is much delayed and appears to be independent of gut morphogenesis. The overall aspects of medaka gut development are similar to those of zebrafish, except that zebrafish tube formation initiates at both the anterior and posterior portions. Our results therefore describe both molecular and morphological aspects of medaka digestive system development that will be necessary for the characterization of medaka mutants. [source] Emilin genes are duplicated and dynamically expressed during zebrafish embryonic developmentDEVELOPMENTAL DYNAMICS, Issue 1 2008Martina Milanetto Abstract Emilins are a family of extracellular matrix proteins with common structural organization and containing a characteristic N-terminal cysteine-rich domain. The prototype of this family, Emilin-1, is found in human and murine organs in association with elastic fibers, and other emilins were recently isolated in mammals. To gain insight into these proteins in lower vertebrates, we investigated the expression of emilins in the fish Danio rerio. Using sequence similarity tools, we identified eight members of this family in zebrafish. Each emilin gene has two paralogs in zebrafish, showing conserved structure with the human ortholog. In situ hybridization revealed that expression of zebrafish emilin genes is regulated in a spatiotemporal manner during embryonic development, with overlapping and site-specific patterns mostly including mesenchymal structures. Expression of certain emilin genes in peculiar areas, such as the central nervous system or the posterior notochord, suggests that they may play a role in key morphogenetic processes. Developmental Dynamics 237:222,232, 2008. © 2007 Wiley-Liss, Inc. [source] Identification of Lmo1 as part of a Hox-dependent regulatory network for hindbrain patterningDEVELOPMENTAL DYNAMICS, Issue 9 2007Christelle Matis Abstract The embryonic functions of Hox proteins have been extensively investigated in several animal phyla. These transcription factors act as selectors of developmental programmes, to govern the morphogenesis of multiple structures and organs. However, despite the variety of morphogenetic processes Hox proteins are involved in, only a limited set of their target genes has been identified so far. To find additional targets, we used a strategy based upon the simultaneous overexpression of Hoxa2 and its cofactors Pbx1 and Prep in a cellular model. Among genes whose expression was upregulated, we identified LMO1, which codes for an intertwining LIM-only factor involved in protein,DNA oligomeric complexes. By analysing its expression in Hox knockout mice, we show that Lmo1 is differentially regulated by Hoxa2 and Hoxb2, in specific columns of hindbrain neuronal progenitors. These results suggest that Lmo1 takes part in a Hox paralogue 2,dependent network regulating anteroposterior and dorsoventral hindbrain patterning. Developmental Dynamics 236:2675,2684, 2007. © 2007 Wiley-Liss, Inc. [source] Temporal and spatial expression profiles of the Fat3 protein, a giant cadherin molecule, during mouse developmentDEVELOPMENTAL DYNAMICS, Issue 2 2007Shigenori Nagae Abstract Cadherins constitute a superfamily of cell,cell interaction molecules that participate in morphogenetic processes of animal development. Fat cadherins are the largest members of this superfamily, with 34 extracellular cadherin repeats. Classic Fat, identified in Drosophila, is known to regulate cell proliferation and planar cell polarity. Although 4 subtypes of Fat cadherin, Fat1, Fat2, Fat3, and Fat4/Fat-J, have been identified in vertebrates, their protein localization remains largely unknown. Here we describe the mRNA and protein distributions of Fat3 during mouse development. We found that Fat3 expression was restricted to the nervous system. In the brain, Fat3 was expressed in a variety of regions and axon fascicles. However, its strongest expression was observed in the olfactory bulb and retina. Detailed analysis of Fat3 in the developing olfactory bulb revealed that Fat3 mRNA was mainly expressed by mitral cells and that its proteins were densely localized along the dendrites of these cells as well as in their axons to some extent. Fat3 transcripts in the retina were expressed by amacrine and ganglion cells, and its proteins were concentrated in the inner plexiform layer throughout development. Based on these observations, we suggest that Fat3 plays a role in the interactions between neurites derived from specific subsets of neurons during development. Developmental Dynamics 236:534,543, 2007. © 2006 Wiley-Liss, Inc. [source] Effects of antisense misexpression of CFC on downstream flectin protein expression during heart loopingDEVELOPMENTAL DYNAMICS, Issue 2 2003Kersti K. Linask Abstract Dextral looping of the heart is regulated on multiple levels. In humans, mutations of the genes CFC and Pitx2/RIEG result in laterality-associated cardiac anomalies. In animal models, a common read-out after the misexpression of laterality genes is heart looping direction. Missing in these studies is how laterality genes impact on downstream morphogenetic processes to coordinate heart looping. Previously, we showed that Pitx2 indirectly regulates flectin protein by regulating the timing of flectin expression in one heart field versus the other (Linask et al. [2002] Dev. Biol. 246:407,417). To address this question further we used a reported loss-of-function approach to interfere with chick CFC expression (Schlange et al. [2001] Dev. Biol. 234:376,389) and assaying for flectin expression during looping. Antisense CFC treatment results in abnormal heart looping or no looping. Our results show that regardless of the sidedness of downstream Pitx2 expression, it is the sidedness of predominant flectin protein expression in the extracellular matrix of the dorsal mesocardial folds and splanchnic mesoderm apposed to the foregut wall that is associated directly with looping direction. Thus, Pitx2 can be experimentally uncoupled from heart looping. The flectin asymmetry continues to be maintained in the secondary heart field during looping. Developmental Dynamics 228:217,230, 2003. © 2003 Wiley-Liss, Inc. [source] Origin of the novel chemoreceptor Aesthetasc "Y" in Ostracoda: morphogenetical thresholds and evolutionary innovationEVOLUTION AND DEVELOPMENT, Issue 2 2008Tomonari Kaji SUMMARY The morphology and developmental processes of the two types of ostracod chemoreceptors, the Aesthetasc "Y" and the "Grouped setae," were compared. Cypridoidea and Pontocypridoidea, belonging to Cypridocopina, have a large baseball bat-like seta as an autapomorphic character on the second antenna, whereas most ostracod taxa with plesiomorphic characters bear "Grouped setae" consisting of multiple setae on the second antenna. Their budding positions, morphology, and ontogenetic changes were compared, and our deduction is that the Aesthetasc "Y" originated from "Grouped setae-like" organ in the Paleozoic. The morphogenetic processes in the molting period of these chemoreceptors were compared at the cellular level. The observations suggest that the "Grouped setae" are formed by hypodermal cells and share sheath cells corresponding to those of the Aesthetasc "Y" as a common constraint in the molting process of setae. We conclude that modification of the morphogenetic processes in the molting period of the "Grouped setae" gave rise to the Aesthetasc "Y" as a novel organ in the evolutionary pathway of the Ostracoda. [source] Properties of ecdysteroid receptors from diverse insect species in a heterologous cell culture system , a basis for screening novel insecticidal candidatesFEBS JOURNAL, Issue 11 2009Joshua M. Beatty Insect development is driven by the action of ecdysteroids on morphogenetic processes. The classic ecdysteroid receptor is a protein heterodimer composed of two nuclear receptors, the ecdysone receptor (EcR) and Ultraspiracle (USP), the insect ortholog of retinoid X receptor. The functional properties of EcR and USP vary among insect species, and provide a basis for identifying novel and species-specific insecticidal candidates that disrupt this receptor's normal activity. A heterologous mammalian cell culture assay was used to assess the transcriptional activity of the heterodimeric ecdysteroid receptor from species representing two major insect orders: the fruit fly, Drosophila melanogaster (Diptera), and the Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera). Several nonsteroidal agonists evoked a strong response with the L. decemlineata heterodimer that was consistent with biochemical and in vivo evidence, whereas the D. melanogaster receptor's response was comparatively modest. Conversely, the phytoecdysteroid muristerone A was more potent with the D. melanogaster heterodimer. The additional presence of juvenile hormone III potentiated the inductive activity of muristerone A in the receptors from both species, but juvenile hormone III was unable to potentiate the inductive activity of the diacylhydrazine methoxyfenozide (RH2485) in the receptor of either species. The effects of USP on ecdysteroid-regulated transcriptional activity also varied between the two species. When it was tested with D. melanogaster EcR isoforms, basal activity was lower and ligand-dependent activity was higher with L. decemlineata USP than with D. melanogaster USP. Generally, the species-based differences validate the use of the cell culture assay screen for novel agonists and potentiators as species-targeted insecticidal candidates. [source] Evolution and phylogenetic relationships of APSES proteins from HemiascomycetesFEMS YEAST RESEARCH, Issue 4 2008Bernardo Ramírez-Zavala Abstract Available complete genomic sequences of hemiascomycetous yeast species were analysed in order to identify the APSES protein family, which belongs to transcriptional factors of the basic helix,loop,helix (bHLH) class. Phylogenetic analyses of the amino acid sequences revealed that a similar set of proteins were present in all yeast species studied. The genome duplication event of Saccharomycetales allows the acquisition of complementary functions between the APSES proteins. Putative ancestors, such as Ashbya gossypii, the Kluyveromyces group and filamentous fungi, only have one APSES protein. Conserved gene order relationships allow the possibility of tracing the evolution of this family and the detection of duplication events. Multiple alignments revealed strict conservation of the APSES motif, although other regions of the APSES proteins were diversified. This review focuses on the evolution of the gene family of APSES proteins in related Hemiascomycetes species; the comparisons could shed light on the functional overlap of these proteins with regard to the regulation of morphogenetic processes and their involvement in the virulence of pathogenic microorganisms. [source] Prenatal craniofacial morphogenesis: four-dimensional visualization of morphogenetic processesORTHODONTICS & CRANIOFACIAL RESEARCH, Issue 2003RJ Radlanski Structured Abstract Author , Radlanski RJ Objectives , Basic research concerning craniofacial development presently runs along two pathways, namely the molecular and the morphometric. This gap needs to be bridged. Design , Using histological serial sections of human fetuses computer-aided three-dimensional reconstructions were made (Software Analysis, SIS) with special focus given to all anatomical structures of the orofacial region of the growing head. Results , All reconstructions can be viewed from any rotation and they are available for virtual dissection according to anatomical rules. As an example, the prenatal development of the human mandible with the formation of the mental foramen therein is described. Furthermore, the spatial arrangement of bone, cartilage and nerves is presented in three dimensions in different developmental stages. The interaction of tissues with possible morphogenetic interaction is discussed. Conclusions , This work serves as a reference system for prenatal development in comparison with pathological development. [source] Development of the vertebrate central nervous system: formation of the neural tubePRENATAL DIAGNOSIS, Issue 4 2009Nicholas D. E. Greene Abstract The developmental process of neurulation involves a series of coordinated morphological events, which result in conversion of the flat neural plate into the neural tube, the primordium of the entire central nervous system (CNS). Failure of neurulation results in neural tube defects (NTDs), severe abnormalities of the CNS, which are among the commonest of congenital malformations in humans. In order to gain insight into the embryological basis of NTDs, such as spina bifida and anencephaly, it is necessary to understand the morphogenetic processes and molecular mechanisms underlying neural tube closure. The mouse is the most extensively studied mammalian experimental model for studies of neurulation, while considerable insight into underlying developmental mechanisms has also arisen from studies in other model systems, particularly birds and amphibians. We describe the process of neural tube formation, discuss the cellular mechanisms involved and highlight recent findings that provide links between molecular signaling pathways and morphogenetic tissue movements. Copyright © 2009 John Wiley & Sons, Ltd. [source] Hepatocyte Growth Factor Receptor, c-Met, in Human Embryo Salivary Glands.ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 3 2010An Immunohistochemical Study With 3 figures and 1 table Summary Salivary gland morphogenesis involves complex, coordinated events that include epithelial,mesenchymal interactions. Mesenchymal,epithelial transition factor (c-Met) is the hepatocyte growth factor (HGF) receptor. The latter is a hepatotropic factor originally identified in rat serum and platelets. It is essential in fetal tissue development, where it regulates complex morphogenetic processes including extracellular matrix invasion, cell migration, cell polarization and tubulogenesis. The c-Met/HGF system is believed to participate in epithelial,mesenchymal interactions during development. Twelve human embryonic minor salivary glands were studied by immunohistochemistry to investigate the role of c-Met in human salivary gland development. Strong c-Met immunopositivity in the glands demonstrated that the molecule is involved in their development and suggested a role for the c-Met/HGF system in this process. [source] | ||||||||||