共查询到20条相似文献，搜索用时 31 毫秒
1.
Whole animal cell sorting of Drosophila embryos 总被引：2，自引：0，他引：2
M A Krasnow S Cumberledge G Manning L A Herzenberg G P Nolan 《Science (New York, N.Y.)》1991,251(4989):81-85
Use of primary culture cells has been limited by the inability to purify most types of cells, particularly cells from early developmental stages. In whole animal cell sorting (WACS), live cells derived from animals harboring a lacZ transgene are purified according to their level of beta-galactosidase expression with a fluorogenic beta-galactosidase substrate and fluorescence-activated cell sorting. With WACS, incipient posterior compartment cells that express the engrailed gene were purified from early Drosophila embryos. Neuronal precursor cells were also purified, and they differentiated into neurons with high efficiency in culture. Because there are many lacZ strains, it may be possible to purify most types of Drosophila cells. The same approach is also applicable to other organisms for which germ-line transformation is possible. 相似文献
2.
Specification of cell fate in the compound eye of Drosophila appears to be controlled entirely by cell interactions. The sevenless gene is required for the correct determination of one of the eight photoreceptor cells (R7) in each ommatidium. It encodes a transmembrane protein with a tyrosine kinase domain and is expressed transiently on a subpopulation of ommatidial precursor cells including the R7 precursors. It is shown here that heat shock-induced indiscriminate expression of a sevenless complementary DNA throughout development can correctly specify R7 cell identity without affecting the development of other cells. Furthermore, discontinuous supply of sevenless protein during eye development leads to the formation of mosaic eyes containing stripes of sevenless+ and sevenless- ommatidia, suggesting that R7 cell fate can be specified only within a relatively short period during ommatidial assembly. These results support the hypothesis that the specification of cell fate by position depends on the interaction of a localized signal with a receptor present on many undifferentiated cells, and that the mere presence of the receptor alone is not sufficient to specify cell fate. 相似文献
3.
Many of the signaling properties of neurons and other electrically excitable cells are determined by a diverse family of potassium channels. A number of genes that encode potassium channel polypeptides have been cloned from various organisms on the basis of their sequence similarity to the Drosophila Shaker (Sh) locus. As an alternative strategy, a molecular analysis of other Drosophila genes that were defined by mutations that perturb potassium channel function was undertaken. Sequence analysis of complementary DNA from the ether à go-go (eag) locus revealed that it encodes a structural component of potassium channels that is related to but is distinct from all identified potassium channel polypeptides. 相似文献
4.
Keller R 《Science (New York, N.Y.)》2002,298(5600):1950-1954
Polarized cell movements shape the major features of the vertebrate body plan during development. The head-to-tail body axis of vertebrates is elongated in embryonic stages by "convergent extension" tissue movements. During these movements cells intercalate between one another transverse to the elongating body axis to form a narrower, longer array. Recent discoveries show that these polarized cell movements are controlled by homologs of genes that control the polarity of epithelial cells in the developing wing and eye of the fruit fly, Drosophila. 相似文献
5.
Wardill TJ List O Li X Dongre S McCulloch M Ting CY O'Kane CJ Tang S Lee CH Hardie RC Juusola M 《Science (New York, N.Y.)》2012,336(6083):925-931
Color and motion information are thought to be channeled through separate neural pathways, but it remains unclear whether and how these pathways interact to improve motion perception. In insects, such as Drosophila, it has long been believed that motion information is fed exclusively by one spectral class of photoreceptor, so-called R1 to R6 cells; whereas R7 and R8 photoreceptors, which exist in multiple spectral classes, subserve color vision. Here, we report that R7 and R8 also contribute to the motion pathway. By using electrophysiological, optical, and behavioral assays, we found that R7/R8 information converge with and shape the motion pathway output, explaining flies' broadly tuned optomotor behavior by its composite responses. Our results demonstrate that inputs from photoreceptors of different spectral sensitivities improve motion discrimination, increasing robustness of perception. 相似文献
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Xotch, the Xenopus homolog of Drosophila notch 总被引：16，自引：0，他引：16
During the development of a vertebrate embryo, cell fate is determined by inductive signals passing between neighboring tissues. Such determinative interactions have been difficult to characterize fully without knowledge of the molecular mechanisms involved. Mutations of Drosophila and the nematode Caenorhabditis elegans have been isolated that define a family of related gene products involved in similar types of cellular inductions. One of these genes, the Notch gene from Drosophila, is involved with cell fate choices in the neurogenic region of the blastoderm, in the developing nervous system, and in the eye-antennal imaginal disc. Complementary DNA clones were isolated from Xenopus embryos with Notch DNA in order to investigate whether cell-cell interactions in vertebrate embryos also depend on Notch-like molecules. This approach identified a Xenopus molecule, Xotch, which is remarkably similar to Drosophila Notch in both structure and developmental expression. 相似文献
9.
Each ommatidium in the compound eye of the Drosophila mutant sevenless lacks photoreceptor number seven (R7) from the normal ommatidial complement of eight photoreceptors. A comparison of mutant and normal development reveals that this deficit is caused by the cell-specific transformation of the cell normally fated to produce R7 into a lens-secreting accessory cell, a cone cell. 相似文献
10.
Cope GA Suh GS Aravind L Schwarz SE Zipursky SL Koonin EV Deshaies RJ 《Science (New York, N.Y.)》2002,298(5593):608-611
COP9 signalosome (CSN) cleaves the ubiquitin-like protein Nedd8 from the Cul1 subunit of SCF ubiquitin ligases. The Jab1/MPN domain metalloenzyme (JAMM) motif in the Jab1/Csn5 subunit was found to underlie CSN's Nedd8 isopeptidase activity. JAMM is found in proteins from archaea, bacteria, and eukaryotes, including the Rpn11 subunit of the 26S proteasome. Metal chelators and point mutations within JAMM abolished CSN-dependent cleavage of Nedd8 from Cul1, yet had little effect on CSN complex assembly. Optimal SCF activity in yeast and both viability and proper photoreceptor cell (R cell) development in Drosophila melanogaster required an intact Csn5 JAMM domain. We propose that JAMM isopeptidases play important roles in a variety of physiological pathways. 相似文献
11.
Cell recognition during neuronal development 总被引：20，自引：0，他引：20
C S Goodman M J Bastiani C Q Doe S du Lac S L Helfand J Y Kuwada J B Thomas 《Science (New York, N.Y.)》1984,225(4668):1271-1279
Insect embryos, with their relatively simple nervous systems, provide a model system with which to study the cellular and molecular mechanisms underlying cell recognition during neuronal development. Such an approach can take advantage of the accessible cells of the grasshopper embryo and the accessible genes of Drosophila. The growth cones of identified neurons express selective affinities for specific axonal surfaces; such specificities give rise to the stereotyped patterns of selective fasciculation common to both species. These and other results suggest that early in development cell lineage and cell interactions lead to the differential expression of cell recognition molecules on the surfaces of small subsets of embryonic neurons whose axons selectively fasciculate with one another. Monoclonal antibodies reveal surface molecules in the Drosophila embryo whose expression correlates with this prediction. It should now be possible to isolate the genes encoding these potential cell recognition molecules and to test their function through the use of molecular genetic approaches in Drosophila. 相似文献
12.
AG Schepers HJ Snippert DE Stange M van den Born JH van Es M van de Wetering H Clevers 《Science (New York, N.Y.)》2012,337(6095):730-735
The concept that tumors are maintained by dedicated stem cells, the so-called cancer stem cell hypothesis, has attracted great interest but remains controversial. Studying mouse models, we provide direct, functional evidence for the presence of stem cell activity within primary intestinal adenomas, a precursor to intestinal cancer. By "lineage retracing" using the multicolor Cre-reporter R26R-Confetti, we demonstrate that the crypt stem cell marker Lgr5 (leucine-rich repeat-containing heterotrimeric guanine nucleotide-binding protein-coupled receptor 5) also marks a subpopulation of adenoma cells that fuel the growth of established intestinal adenomas. These Lgr5(+) cells, which represent about 5 to 10% of the cells in the adenomas, generate additional Lgr5(+) cells as well as all other adenoma cell types. The Lgr5(+) cells are intermingled with Paneth cells near the adenoma base, a pattern reminiscent of the architecture of the normal crypt niche. 相似文献
13.
大豆花叶病毒症状反应的遗传研究 总被引：2，自引：0，他引：2
利用对SMV不同株系分别表现抗病（免疫或无症状）、坏死以及花叶的品种，配置花叶×抗病，花叶×花叶、花叶×坏死，坏死×坏死、坏死×抗病5类杂交组合。各组合的F1、F2和部分B1、F3世代在接种大豆花叶病毒Sa, SC8和N3株系的条件下，研究了大豆花叶病毒症状反应的遗传。结果表明，花叶×抗病组合接种SC8株系后，F1表现抗病，F2和B1群体分别发生3抗∶1感以及1抗∶1感的表型和基因型分离，说明一对等位基因控制大豆对SC8 的抗病和花叶症状，其中抗病表现显性，花叶表现隐性。花叶×坏死组合接种SC8和Sa后，F1表现坏死，F2群体发生3坏死∶1花叶分离，说明控制坏死和花叶症状的基因是等位的，坏死基因对花叶基因表现为显性。坏死×抗病组合的F1表现抗病，F2出现3抗∶1坏死分离，说明抗病对坏死为显性。坏死×坏死，花叶×花叶两类组合后代接种不同株系后均没有发生症状分离，说明不同品种间控制花叶的基因是等位的；控制坏死的基因也是等位的。根据以上遗传试验推断，大豆对SMV的抗病（无症状）、坏死以及花叶3类症状由1组复等位基因控制，对应的等位基因可分别表示为S R、s N和s m，其中S R对s N和s m均表现显性，s N对s m表现显性。 相似文献
14.
Lipid phosphates can act as signaling molecules to influence cell division, apoptosis, and migration. wunen and wunen2 encode Drosophila lipid phosphate phosphohydrolases, integral membrane enzymes that dephosphorylate extracellular lipid phosphates. wun and wun2 act redundantly in somatic tissues to repel migrating germ cells, although the mechanism by which germ cells respond is unclear. Here, we report that wun2 also functions in germ cells, enabling them to perceive the wun/wun2-related signal from the soma. Upon Wun2 expression, cultured insect cells dephosphorylate and internalize exogenously supplied lipid phosphate. We propose that Drosophila germ cell migration and survival are controlled by competition for hydrolysis of a lipid phosphate between germ cells and soma. 相似文献
15.
In the membrane of the flight muscle cells of developing Drosophila a large calcium-sensitive potassium current, IKc, was found. It was present before the development of voltage-activated potassium channels and seems to be the first potassium current to develop in the membrane. Also present in these early cells were large numbers of occult (hidden) calcium channels, which remained inactive until the end of pupal development. These inactive calcium channels could be made to function by injecting adenosine triphosphate or ethyleneglycol tetraacetic acid into the early cells. IKc has kinetic properties resembling the later developing voltage-sensitive current IKv, and is distinct from the fast, transient calcium-dependent outward current IAc, which appears much later in development. IAc closely resembles the voltage-sensitive current IAv, also present in these cells. Thus, both of the voltage-sensitive potassium channel types, IAv and IKv, have similar calcium-sensitive counterparts, IAc and IKc, that are present in the same cells. 相似文献
16.
Cytonemes are types of filopodia in the Drosophila wing imaginal disc that are proposed to serve as conduits in which morphogen signaling proteins move between producing and target cells. We investigated the specificity of cytonemes that are made by target cells. Cells in wing discs made cytonemes that responded specifically to Decapentaplegic (Dpp) and cells in eye discs made cytonemes that responded specifically to Spitz (the Drosophila epidermal growth factor protein). Tracheal cells had at least two types: one made in response to Branchless (a Drosophila fibroblast growth factor protein, Bnl), to which they segregate the Bnl receptor, and another to which they segregate the Dpp receptor. We conclude that cells can make several types of cytonemes, each of which responds specifically to a signaling pathway by means of the selective presence of a particular signaling protein receptor that has been localized to that cytoneme. 相似文献
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Stromal cells are thought to generate specific regulatory microenviroments or "niches" that control stem cell behavior. Characterizing stem cell niches in vivo remains an important goal that has been difficult to achieve. The individual ovarioles of the Drosophila ovary each contain about two germ line stem cells that maintain oocyte production. Here we show that anterior ovariolar somatic cells comprising three cell types act as a germ line stem cell niche. Germ line stem cells lost by normal or induced differentiation are efficiently replaced, and the ability to repopulate the niche increases the functional lifetime of ovarioles in vivo. Our studies implicate one of the somatic cell types, the cap cells, as a key niche component. 相似文献
19.
Translocation and rearrangements of the c-myc oncogene locus in human undifferentiated B-cell lymphomas 总被引：61，自引：0，他引：61
R Dalla-Favera S Martinotti R C Gallo J Erikson C M Croce 《Science (New York, N.Y.)》1983,219(4587):963-967
The locus for the cellular myc (c-myc) oncogene in humans is located on the region of chromosome 8 that is translocated to chromosome 14 in cells from most undifferentiated B-cell lymphomas. It is shown in this study that the c-myc locus is rearranged in 5 out of 15 cell lines from patients with undifferentiated B-cell lymphomas, and that the rearrangement involves a region at the 5' side of an apparently intact c-myc gene. In at least three patients, this rearranged region appears to contain immunoglobulin heavy chain mu sequences that are located on chromosome 14. The data indicate that this region contains the crossover point between chromosomes 8 and 14. The break point can occur at different positions on both chromosomes among individual cell lines. 相似文献
20.
Photoreceptor deactivation and retinal degeneration mediated by a photoreceptor-specific protein kinase C 总被引：13，自引：0，他引：13
D P Smith R Ranganathan R W Hardy J Marx T Tsuchida C S Zuker 《Science (New York, N.Y.)》1991,254(5037):1478-1484
The protein kinase C (PKC) family of serine-threonine kinases has been implicated in the regulation of a variety of signaling cascades. One member of this family, eye-PKC, is expressed exclusively in the Drosophila visual system. The inaC (inactivation-no-afterpotential C) locus was shown to be the structural gene for eye-PKC. Analysis of the light response from inaC mutants showed that this kinase is required for the deactivation and rapid desensitization of the visual cascade. Light adaptation was also defective in inaC mutant flies. In flies carrying the retinal degeneration mutation rdgB, absence of eye-PKC suppressed photoreceptor cell degeneration. These results indicate that eye-PKC functions in the light-dependent regulation of the phototransduction cascade in Drosophila. 相似文献