Search results for "La Protein"
showing 10 items of 245 documents
aPKCζ cortical loading is associated with Lgl cytoplasmic release and tumor growth in Drosophila and human epithelia
2007
Atypical protein kinase C (aPKC) and Lethal giant larvae (Lgl) regulate apical-basal polarity in Drosophila and mammalian epithelia. At the apical domain, aPKC phosphorylates and displaces Lgl that, in turn, maintains aPKC inactive at the basolateral region. The mutual exclusion of these two proteins seems to be crucial for the correct epithelial structure and function. Here we show that a cortical aPKC loading induces Lgl cytoplasmic release and massive overgrowth in Drosophila imaginal epithelia, whereas a cytoplasmic expression does not alter proliferation and epithelial overall structure. As two aPKC isoforms (iota and zeta) exist in humans and we previously showed that Drosophila Lgl i…
Filopodia-like actin cables position nuclei in association with perinuclear actin in Drosophila nurse cells
2013
Summary Controlling the position of the nucleus is vital for a number of cellular processes from yeast to humans. In Drosophila nurse cells, nuclear positioning is crucial during dumping, when nurse cells contract and expel their contents into the oocyte. We provide evidence that in nurse cells, continuous filopodia-like actin cables, growing from the plasma membrane and extending to the nucleus, achieve nuclear positioning. These actin cables move nuclei away from ring canals. When nurse cells contract, actin cables associate laterally with the nuclei, in some cases inducing nuclear turning so that actin cables become partially wound around the nuclei. Our data suggest that a perinuclear a…
A GFP-tagged Muscleblind C protein isoform reporter construct
2010
Drosophila muscleblind (mbl), the ortholog of human Muscleblind-like 1 (MBNL1) gene involved in Myotonic Dystrophy (DM), gives raise to protein isoforms MblA to G. The specific functions and subcellular distribution of isoforms are still largely unknown. To overcome the lack of isoform-specific antibodies we generated transgenic flies that express a GFP:MblC fusion protein under the control of the Gal4/UAS system. The reporter fusion protein was able to functionally complement mbl loss of function mutations, demonstrating activity, and accumulated predominantly in adult muscle nuclei. The fluorescent nature of the reporter makes it appropriate for live imaging detection of MblC protein isof…
Predetermined embryonic glial cells form the distinct glial sheaths of the Drosophila peripheral nervous system
2013
International audience; One of the numerous functions of glial cells in Drosophila is the ensheathment of neurons to isolate them from the potassium-rich haemolymph, thereby establishing the blood-brain barrier. Peripheral nerves of flies are surrounded by three distinct glial cell types. Although all embryonic peripheral glia (ePG) have been identified on a single-cell level, their contribution to the three glial sheaths is not known. We used the Flybow system to label and identify each individual ePG in the living embryo and followed them into third instar larva. We demonstrate that all ePG persist until the end of larval development and some even to adulthood. We uncover the origin of al…
Timing of identity: spatiotemporal regulation of hunchback in neuroblast lineages of Drosophila by Seven-up and Prospero.
2006
Neural stem cells often generate different cell types in a fixed birth order as a result of temporal specification of the progenitors. In Drosophila, the first temporal identity of most neural stem cells(neuroblasts) in the embryonic ventral nerve cord is specified by the transient expression of the transcription factor Hunchback. When reaching the next temporal identity, this expression is switched off in the neuroblasts by seven up (svp) in a mitosis-dependent manner, but is maintained in their progeny (ganglion mother cells). We show that svpmRNA is already expressed in the neuroblasts before this division. After mitosis, Svp protein accumulates in both cells, but the downregulation of h…
The ladybird homeobox genes are essential for the specification of a subpopulation of neural cells
2004
AbstractIn Drosophila, neurons and glial cells are produced by neural precursor cells called neuroblasts (NBs), which can be individually identified. Each NB generates a characteristic cell lineage specified by a precise spatiotemporal control of gene expression within the NB and its progeny. Here we show that the homeobox genes ladybird early and ladybird late are expressed in subsets of cells deriving from neuroblasts NB 5-3 and NB 5-6 and are essential for their correct development. Our analysis revealed that ladybird in Drosophila, like their vertebrate orthologous Lbx1 genes, play an important role in cell fate specification processes. Among those cells that express ladybird are NB 5-6…
A critical role for Cyclin E in cell fate determination in the central nervous system of Drosophila melanogaster
2004
We have examined the process by which cell diversity is generated in neuroblast (NB) lineages in the central nervous system of Drosophila melanogaster. Thoracic NB6-4 (NB6-4t) generates both neurons and glial cells, whereas NB6-4a generates only glial cells in abdominal segments. This is attributed to an asymmetric first division of NB6-4t, localizing prospero (pros) and glial cell missing (gcm) only to the glial precursor cell, and a symmetric division of NB6-4a, where both daughter cells express pros and gcm. Here we show that the NB6-4t lineage represents the ground state, which does not require the input of any homeotic gene, whereas the NB6-4a lineage is specified by the homeotic genes…
Comm Sorts Robo to Control Axon Guidance at the Drosophila Midline
2002
AbstractAxon growth across the Drosophila midline requires Comm to downregulate Robo, the receptor for the midline repellent Slit. We show here that comm is required in neurons, not in midline cells as previously thought, and that it is expressed specifically and transiently in commissural neurons. Comm acts as a sorting receptor for Robo, diverting it from the synthetic to the late endocytic pathway. A conserved cytoplasmic LPSY motif is required for endosomal sorting of Comm in vitro and for Comm to downregulate Robo and promote midline crossing in vivo. Axon traffic at the CNS midline is thus controlled by the intracellular trafficking of the Robo guidance receptor, which in turn depends…
Charting the Drosophila neuropile: a strategy for the standardised characterisation of genetically amenable neurites
2003
Insect neurons are individually identifiable and have been used successfully to study principles of the formation and function of neuronal circuits. In the fruitfly Drosophila, studies on identifiable neurons can be combined with efficient genetic approaches. However, to capitalise on this potential for studies of circuit formation in the CNS of Drosophila embryos or larvae, we need to identify pre- and postsynaptic elements of such circuits and describe the neuropilar territories they occupy. Here, we present a strategy for neurite mapping, using a set of evenly distributed landmarks labelled by commercially available anti-Fasciclin2 antibodies which remain comparatively constant between s…
Spatio-temporal pattern of cells expressing the clock genes period and timeless and the lineages of period expressing neurons in the embryonic CNS of…
2010
The initial steps towards the generation of cell diversity in the central nervous system of the fruitfly Drosophila melanogaster take place during early phases of embryonic development when a stereotypic population of neural progenitor cells (neuroblasts and midline precursors) is formed in a precise spatial and temporal pattern, and subsequently expresses a particular sequence of genes. The clarification of the positional, temporal and molecular features of the individual progenitor cells in the nerve cord and brain as well as of their specific types of neuronal and/or glial progeny cells forms an essential basis to understand the mechanisms controlling their development. The present study…