Functional analysis of an ascidian homologue of vertebrate Bmp-2/Bmp-4 suggests its role in the inhibition of neural fate specification

Development ◽  
1997 ◽  
Vol 124 (24) ◽  
pp. 5149-5159 ◽  
Author(s):  
T. Miya ◽  
K. Morita ◽  
A. Suzuki ◽  
N. Ueno ◽  
N. Satoh
Keyword(s):  
Sequence Similarity ◽  
Neural Tissue ◽  
Muscle Cells ◽  
Cell Interaction ◽  
Cellular Interaction ◽  
Cellular Interactions ◽  
Halocynthia Roretzi ◽  
Functional Conservation ◽  
Neural Fate ◽  
Mode Of Development

The ascidian tadpole larva is thought to be close to a prototype of the ancestral chordate. The vertebrate body plan is established by a series of inductive cellular interactions, whereas ascidians show a highly determinate mode of development. Recent studies however, suggest some roles of cell-cell interaction during ascidian embryogenesis. To elucidate the signaling molecules responsible for the cellular interaction, we isolated HrBMPb, an ascidian homologue of the vertebrate bone morphogenetic protein (BMP) gene, from Halocynthia roretzi. The amino acid sequence of HrBMPb closely resembled those of vertebrate BMP-2 and BMP-4 and of Drosophila Decapentaplegic (DPP). In addition to the sequence similarity, HrBMPb overexpression induced the ventralization of Xenopus embryos, suggesting functional conservation. The zygotic expression of HrBMPb was first detected around gastrulation. HrBMPb expression was maintained in some cells at the lateral edges of the neural plate through gastrulation to neurulation, although that in the presumptive muscle cells was downregulated. HrBMPb was not expressed in the presumptive epidermis during gastrulation. When HrBMPb mRNA was injected into fertilized Halocynthia eggs, cells that normally give rise to the neural tissue differentiated into epidermis, causing a loss of anterior neural tissue in the larva. In addition, HrBMPb might function synergistically with HrBMPa, an ascidian homologue of BMPs-5 to 8. However, HrBMPb overexpression did not affect differentiation of the notochord and muscle cells. These results suggest that HrBMPb functions as a neural inhibitor and as an epidermal inducer but not as a ventralizing agent in ascidian development.

scholarly journals Proteomic and biochemical comparison of the cellular interaction partners of human VPS33A and VPS33B

2017 ◽  
Author(s):  
Morag R. Hunter ◽  
Geoffrey G. Hesketh ◽  
Anne-Claude Gingras ◽  
Stephen C. Graham
Keyword(s):  
Sequence Similarity ◽  
Domain Architecture ◽  
Gel Filtration ◽  
Cellular Interaction ◽  
Class Iii ◽  
Phosphatidylinositol 3 Kinase ◽  
Protein Subunit ◽  
Over Expression ◽  
Biochemical Comparison

ABSTRACTMulti-subunit tethering complexes control membrane fusion events in eukaryotic cells. CORVET and HOPS are two such multi-subunit tethering complexes, both containing the Sec1/Munc18 protein subunit VPS33A. Metazoans additionally possess VPS33B, which has considerable sequence similarity to VPS33A but does not integrate into CORVET or HOPS complexes and instead stably interacts with VIPAR. It has been recently suggested that VPS33B and VIPAR comprise two subunits of a novel multi-subunit tethering complex (named ‘CHEVI’), analogous in configuration to CORVET and HOPS. We utilised the BioID proximity biotinylation assay to compare and contrast the interactomes of VPS33A and VPS33B. Overall, few proteins were identified as associating with both VPS33A and VPS33B, suggesting these proteins have distinct sub-cellular localisations. Consistent with previous reports, we observed that VPS33A was co-localised with many components of class III phosphatidylinositol 3-kinase (PI3KC3) complexes: PIK3C3, PIK3R4, NRBF2, UVRAG and RUBICON. Although in this assay VPS33A clearly co-localised with several subunits of CORVET and HOPS, no proteins with the canonical CORVET/HOPS domain architecture were found to co-localise with VPS33B. Instead, we identified two novel VPS33B-interacting proteins, VPS53 and CCDC22. CCDC22 co-immunoprecipitated with VPS33B and VIPAR in over-expression conditions and interacts directly with the VPS33B-VIPAR complex in vitro. However, CCDC22 does not appear to co-fractionate with VPS33B and VIPAR in gel filtration of human cell lysates. We also observed that the protein complex in HEK293T cells which contained VPS33B and VIPAR was considerably smaller than CORVET/HOPS, suggesting that, unlike VPS33A, VPS33B does not assemble into a large stable multi-subunit tethering complex.

scholarly journals Interacting cell populations in cultures of leukocytes from normal or leukemic peripheral blood

Blood ◽  
1977 ◽  
Vol 49 (2) ◽  
pp. 269-280
Keyword(s):  
Thymidine Incorporation ◽  
Kinetic Studies ◽  
Cell Interaction ◽  
Cell Number ◽  
Cellular Interaction ◽  
Intact Cells ◽  
Quantitative Evidence ◽  
Peripheral Leukocytes ◽  
Limiting Dilution ◽  
Stimulation Of

Kinetic studies in cultures containing 2 X 10(5) peripheral leukocytes from patients with acute myelobastic leukemia revealed extensive, radiation-sensitive increases in thymidine incorporation without parallel increases in cell number. Modest and variable stimulation of 3HTdR incorporation was seen with the addition of either leukocyte- conditioned medium prepared with phytohemagglutin (PHA) or PHA alone. However, using the method of limiting dilution, stimulation was always observed and ranged from 3- to 20-fold in individual patients. By mixing small numbers of intact cells with larger numbers of irradiated autologous cells, quantitative evidence was obtained for a cellular interaction between irradiated, PHA-stimulated populations capable of 3HTdR incorporation. Similar evidence for cell-cell interaction was obtained for normal leukocytes.

Proneural clusters: equivalence groups in the epithelium of Drosophila

Development ◽  
1990 ◽  
Vol 110 (3) ◽  
pp. 927-932 ◽  
Author(s):  
P. Simpson ◽  
C. Carteret
Keyword(s):  
Nervous System ◽  
Cell Lineage ◽  
Cellular Interactions ◽  
Equivalence Group ◽  
Neural Fate ◽  
Axonal Projections ◽  
The Central Nervous System ◽  
Neuronal Specificity ◽  
Proneural Cluster ◽  
Do So

The segregation of neural precursors from epidermal cells during development of the nervous system of Drosophila relies on interactions between cells that are thought to be initially equivalent. During development of the adult peripheral nervous system, failure of the cellular interactions leads to the differentiation of a tuft of sensory bristles at the site where usually only one develops. It is thus thought that a group of cells at that site (a proneural cluster) has the potential to make a bristle but that in normal development only one cell will do so. The question addressed here is do these cells constitute an equivalence group (Kimble, J., Sulston, J. and White, J. (1979). In Cell Lineage, Stem Cells and Cell Determination (ed. N. Le Douarin). Inserm Symposium No. 10 pp. 59–68, Elsevier, Amsterdam)? Within clusters mutant for shaggy, where several cells of a cluster follow the neural fate and differentiate bristles, it is shown that these display identical neuronal specificity: stimulation of the bristles evoke the same leg cleaning response and backfilling of single neurons reveal similar axonal projections in the central nervous system. This provides direct experimental evidence that the cells of a proneural cluster are developmentally equivalent.

scholarly journals Cell–Cell Interaction of Macrophages and Vascular Smooth Muscle Cells in the Synthesis of Leukotriene B4

1994 ◽  
Vol 3 (4) ◽  
pp. 297-302 ◽  
Author(s):  
M. Zou ◽  
C. Anges
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Muscle Cells ◽  
Cell Interaction ◽  
Leukotriene B4 ◽  
Factor Α ◽  
Dose Dependent ◽  
Cell Cell

Biosynthesis of LTB4during cell-cell interaction between vascular smooth muscle cells (SMC) and alveolar macrophages (AM) has been investigated by use of both high-pressure Hquid chromatography (HPLC) and radtoimmunoassay (RIA). Both interleukin-β (IL-β) and tumour necrosis factor-α (TNFα) induced a time- and dose-dependent synthesis of 15-, and 5-hydroxyeicosatetraenoic acids (HETEs) from cultured SMC. However, neither TNFα nor IL-1β induced a significant LTB4production in SMC alone or AM alone after 24 h of incubation. Addition of IL-1β and TNFα simultaneously to SMC resulted in a dose-dependent synergistic increase of HETEs. Macrophages dose-dependently transformed extremely low concentrations of exogenous LTA4into LTB4. Incubation of vascular SMC with various numbers of AM in the presence of IL-1β (5 units/ml) and TNFα (10 units/ml) induced a great increase of LTB4synthesis in comparison with the detectable levels of LTB4produced by macrophages alone. Pretreatment of SMC with NDGA, cycloheximide, and actinomycin not only inhibited IL-1 and TNT induced HETEs synthesis but also abolished LTB4production when co-incubated with macrophages. These results suggest that LTB4in a mixture of SMC and macrophages could originate from a transcellular metabolism, i.e. macrophages transforming SMC-derived LTA4into LTB4.

scholarly journals THE HISTOGENESIS OF RAT INTERCOSTAL MUSCLE

1969 ◽  
Vol 42 (1) ◽  
pp. 135-153 ◽  
Author(s):  
A. M. Kelly ◽  
S. I. Zacks
Keyword(s):  
Muscle Cells ◽  
Small Cells ◽  
Intercostal Muscle ◽  
Undifferentiated Cells ◽  
Single Well ◽  
Muscle Groups ◽  
Well Differentiated ◽  
Mode Of Development ◽  
Developing System ◽  
Developing Muscle

Intercostal muscle from fetal and newborn rats was examined with the electron microscope. At 16 days' gestation, the developing muscle was composed of primary generations of myotubes, many of which were clustered together in groups. Within these groups, the membranes of neighboring myotubes were interconnected by specialized junctions, including tight junctions. Morphologically undifferentiated cells surrounded the muscle groups, frequently extended pseudopodia along the interspace between adjacent myotubes, and appeared to separate neighboring myotubes from one another. At 18 and 20 days' gestation, the muscle was also composed of groups of cells but the structure of the groups differed from that of the groups observed at 16 days. Single, well differentiated myotubes containing much central glycogen and peripheral myofibrils dominated each group. These large cells were interpreted as primary myotubes. Small, less differentiated muscle cells and undifferentiated cells clustered around their walls. Each cluster was ensheated by a basal lamina. The small cells were interpreted as primordia of new generations of muscle cells which differentiated by appositional growth along the walls of the large primary myotubes. All generations of rat intercostal muscle cells matured to myofibers between 20 days' gestation and birth. Coincidentally, large and small myofibers diverged from each other, leading to disintegration of the groups of muscle cells. Undifferentiated cells frequently occurred in the interspaces between neighboring muscle cells at the time of separation. Myofibers arising at different stages of muscle histogenesis intermingled in a checkerboard fashion as a result of this asynchronous mode of development. The possibility of fusion between neighboring muscle cells in this developing system is discussed.

Development of Transient Outward Currents Coupled With Ca2+-Induced Ca2+ Release Mediates Oscillatory Membrane Potential in Ascidian Muscle Cells

2004 ◽  
Vol 92 (2) ◽  
pp. 1056-1066 ◽  
Author(s):  
Koichi Nakajo ◽  
Yasushi Okamura
Keyword(s):  
Membrane Potential ◽  
Voltage Clamp ◽  
Muscle Cell ◽  
Single Channel ◽  
Muscle Cells ◽  
Developmental Expression ◽  
Dependent Manner ◽  
Membrane Excitability ◽  
Halocynthia Roretzi ◽  
Outward Currents

Isolated ascidian Halocynthia roretzi blastomeres of the muscle lineage exhibit muscle cell-like excitability on differentiation despite the arrest of cell cleavage early in development. This characteristic provides a unique opportunity to track changes in ion channel expression during muscle cell differentiation. Here, we show that the intrinsic membrane property of ascidian cleavage-arrested muscle-type cells becomes oscillatory by expressing transient outward currents ( Ito) activated by Ca2+-induced Ca2+ release (CICR) in a maturation-dependent manner. In current-clamp mode, most day 4 (72 h after fertilization) cleavage-arrested muscle cells exhibited an oscillatory membrane potential of –20 mV at 15 Hz, whereas most day 3 (48 h after fertilization) cells exhibited a spiking pattern. In voltage-clamp mode, the day 4 cells exhibited prominent transient outward currents that were not present in day 3 cells. Ito was abolished by the application of 10 mM caffeine, implying that CICR was involved in Ito activation. Ito was based on K+ efflux and sensitive to tetraethylammonium and some Ca2+-activated K+ channel inhibitors. We found a 60-pS single channel conductance that was activated by local Ca2+ release in ascidian muscle cell. Voltage-clamp recording with an oscillatory waveform as a command pulse showed that CICR-activated K+ currents were activated during the falling phase of the membrane potential oscillation. These results suggest that developmental expression of CICR-activated K+ current plays a role in the maturation of larval locomotion by modifying the intrinsic membrane excitability of muscle cells.

scholarly journals Cytotoxic T lymphocyte responses in allogeneic radiation bone marrow chimeras. The chimeric host strictly dictates the self-repertoire of Ia-restricted T cells but not H-2K/D-restricted T cells.

1982 ◽  
Vol 156 (6) ◽  
pp. 1650-1664 ◽  
Author(s):  
S M Bradley ◽  
A M Kruisbeek ◽  
A Singer
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Cell Interaction ◽  
The Self ◽  
Cellular Interactions ◽  
Stringent Requirement ◽  
Th Cells ◽  
Donor Type ◽  
Bone Marrow Chimeras ◽  
Ctl Responses

The present report has used fully H-2 allogeneic radiation bone marrow chimeras to assess the role of host restriction elements in determining the self-specificity of Ia- and H-2K/D-restricted T cells that participate in the generation of trinitrophenyl (TNP)-specific cytotoxic T lymphocytes (CTL). It was demonstrated that there exists a stringent requirement for the recognition of host thymic-type Ia determinants, but there exists only a preference for host thymic-type H-2K/D determinants. Indeed, once the stringent requirement for recognition of host Ia determinants was fulfilled, anti-TNP CTL were generated in response to TNP-modified stimulators that expressed either donor-type or host-type H-2K/D determinants. The CTL that were generated in response to TNP-modified donor-type stimulators were shown to be specific for TNP and restricted to the non-thymic H-2K/D determinants of the chimeric donor. Thus, these results demonstrate in a single immune response that the thymic hypothesis accurately predicts the self-specificity expressed by Ia-restricted T cells, but does not fully account for the self-specificity expressed by H-2K/D-restricted T cells. These results are consistent with the concept that H-2K/D-restricted T cells, but not Ia-restricted T cells, can differentiate into functional competence either intrathymically or extra-thymically. The present results are also informative for understanding the cellular interactions that are required for the generation of antigen-specific CTL responses. The Ia-restricted T cells that are required for the generation of H-2K/D-restricted anti-TNP CTL were shown to be helper T (TH) cells since (a) like TH cells functioning in antibody responses, they were specific for Ia determinants expressed by accessory cells, and (b) their function could be replaced by either TNP-primed, irradiated TH cells or by nonspecific soluble helper factors. It was also shown that the T-T cell interaction between Ia-restricted TH cells and H-2K/D-restricted precursor CTL (pCTL) is not Ia restricted. Rather, the results demonstrate that the generation of anti-TNP CTL responses involve two parallel sets of major histocompatibility complex-restricted cell interactions, an Ia-restricted TH-accessory cell interaction required for TH cell activation, and an H-2K/D-restricted pCTL-stimulator cell interaction required for pCTL stimulation. The interaction between activated TH cells and stimulated pCTL is mediated, at least in part, by nonspecific soluble helper factors.

Litoreibacter halocynthiae sp. nov., isolated from the sea squirt Halocynthia roretzi

2013 ◽  
Vol 63 (Pt_9) ◽  
pp. 3364-3368 ◽  
Author(s):  
Young-Ok Kim ◽  
Sooyeon Park ◽  
Bo-Hye Nam ◽  
Yong-Taek Jung ◽  
Dong-Gyun Kim ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Sequence Similarity ◽  
Phylogenetic Analyses ◽  
Rrna Gene ◽  
Halocynthia Roretzi ◽  
Content Type ◽  
Link Type ◽  
Sea Squirt ◽  
Type Strains

A Gram-stain-negative, non-motile and coccoid, ovoid or rod-shaped bacterial strain, designated P-MA1-7T, was isolated from a sea squirt (Halocynthia roretzi) collected from the South Sea, Korea. Strain P-MA1-7T grew optimally at 25 °C, at pH 7.0–8.0 and in the presence of 2–3 % (w/v) NaCl. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain P-MA1-7T fell within the cluster comprising the type strains of four species of the genus Litoreibacter , exhibiting 16S rRNA gene sequence similarity values of 97.0–98.5 % to these four type strains and less than 95.9 % sequence similarity to the strains of the other species examined. Strain P-MA1-7T contained Q-10 as the predominant ubiquinone and C18 : 1ω7c as the predominant fatty acid. The major polar lipids of strain P-MA1-7T were phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, one unidentified aminolipid and one unidentified lipid. The DNA G+C content of strain P-MA1-7T was 58.3 mol% and DNA–DNA relatedness values of strain P-MA1-7T with the type strains of the four species of the genus Litoreibacter were in the range of 8–21 %. The differential phenotypic properties, together with the phylogenetic and genetic distinctiveness, revealed that strain P-MA1-7T was separate from other species of the genus Litoreibacter . On the basis of these data, strain P-MA1-7T is considered to represent a novel species of the genus Litoreibacter , for which the name Litoreibacter halocynthiae sp. nov. is proposed. The type strain is P-MA1-7T ( = KCTC 32213T = CCUG 63416T).

scholarly journals Annotation Transfer for Genomics: Measuring Functional Divergence in Multi-Domain Proteins

2001 ◽  
Vol 11 (10) ◽  
pp. 1632-1640
Author(s):  
Hedi Hegyi ◽  
Mark Gerstein
Keyword(s):  
Genome Annotation ◽  
Large Scale ◽  
Sequence Similarity ◽  
Functional Divergence ◽  
Open Reading Frames ◽  
Single Domain ◽  
Functional Conservation ◽  
Link Type ◽  
Approximate Function ◽  
The Relationship

Annotation transfer is a principal process in genome annotation. It involves “transferring” structural and functional annotation to uncharacterized open reading frames (ORFs) in a newly completed genome from experimentally characterized proteins similar in sequence. To prevent errors in genome annotation, it is important that this process be robust and statistically well-characterized, especially with regard to how it depends on the degree of sequence similarity. Previously, we and others have analyzed annotation transfer in single-domain proteins. Multi-domain proteins, which make up the bulk of the ORFs in eukaryotic genomes, present more complex issues in functional conservation. Here we present a large-scale survey of annotation transfer in these proteins, using scop superfamilies to define domain folds and a thesaurus based on SWISS-PROT keywords to define functional categories. Our survey reveals that multi-domain proteins have significantly less functional conservation than single-domain ones, except when they share the exact same combination of domain folds. In particular, we find that for multi-domain proteins, approximate function can be accurately transferred with only 35% certainty for pairs of proteins sharing one structural superfamily. In contrast, this value is 67% for pairs of single-domain proteins sharing the same structural superfamily. On the other hand, if two multi-domain proteins contain the same combination of two structural superfamilies the probability of their sharing the same function increases to 80% in the case of complete coverage along the full length of both proteins, this value increases further to > 90%. Moreover, we found that only 70 of the current total of 455 structural superfamilies are found in both single and multi-domain proteins and only 14 of these were associated with the same function in both categories of proteins. We also investigated the degree to which function could be transferred between pairs of multi-domain proteins with respect to the degree of sequence similarity between them, finding that functional divergence at a given amount of sequence similarity is always about two-fold greater for pairs of multi-domain proteins (sharing similarity over a single domain) in comparison to pairs of single-domain ones, though the overall shape of the relationship is quite similar. Further information is available athttp://partslist.org/func orhttp://bioinfo.mbb.yale.edu/partslist/func.

Sign in / Sign up

Export Citation Format

Share Document