Apoptosis of the midline glia during Drosophila embryogenesis: a correlation with axon contact

Development ◽  
1995 ◽  
Vol 121 (2) ◽  
pp. 569-578 ◽  
Author(s):  
M.J. Sonnenfeld ◽  
J.R. Jacobs
Keyword(s):  
Cell Death ◽  
Nerve Cord ◽  
Time Course ◽  
Ventral Nerve Cord ◽  
Ectopic Expression ◽  
Wild Type ◽  
Drosophila Embryogenesis ◽  
Quantitative Studies ◽  
The Central Nervous System ◽  
Drosophila Embryos

We have examined cell death within lineages in the midline of Drosophila embryos. Approximately 50% of cells within the anterior, middle and posterior midline glial (MGA, MGM and MGP) lineages died by apoptosis after separation of the commissural axon tracts. Glial apoptosis is blocked in embryos deficient for reaper, where greater than wild-type numbers of midline glia (MG) are present after stage 12. Quantitative studies revealed that MG death followed a consistent temporal pattern during embryogenesis. Apoptotic MG were expelled from the central nervous system and were subsequently engulfed by phagocytic haemocytes. MGA and MGM survival was apparently dependent upon proper axonal contact. In embryos mutant for the commissureless gene, a decrease in axon-glia contact correlated with a decrease in MGA and MGM survival and accelerated the time course of MG death. In embryos mutant for the slit gene, MGA and MGM maintained contact with longitudinally and contralaterally projecting axons and MG survival was comparable to that in wild-type embryos. The initial number of MG within individual ventral nerve cord segments was increased by ectopic expression of the rhomboid gene, without changing axon number. Extra MGA and MGM were eliminated from the ventral nerve cord by apoptosis to restore wild-type numbers of midline glia. Ectopic rhomboid expression also shifted MGA and MGM cell death to an earlier stage of embryogenesis. One possible explanation is that axon-glia contact or communication promotes survival of the MG and that MG death may result from a competition for available axon contact.

Distribution of gamma-aminobutyric acid (GABA) in the central nervous system of the male mud crab, Scylla olivacea

Crustaceana ◽  
2020 ◽  
Vol 93 (9-10) ◽  
pp. 1123-1134
Author(s):  
Kanjana Khornchatri ◽  
Jirawat Saetan ◽  
Sirirak Mukem ◽  
Prasert Sobhon ◽  
Tipsuda Thongbuakaew
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Distribution Pattern ◽  
Nerve Cord ◽  
Ventral Nerve Cord ◽  
Aminobutyric Acid ◽  
Gamma Aminobutyric Acid ◽  
Mud Crab ◽  
Decapod Crustaceans ◽  
The Central Nervous System

Abstract Gamma-aminobutyric acid (GABA) is a neurotransmitter that is widely spread in vertebrate and invertebrate nervous systems and modulates essential physiological roles. Previous studies have reported the distribution of several neurotransmitters throughout the central nervous system (CNS) of decapod crustaceans. However, the existence and distribution of GABA in the mud crab’s, Scylla olivacea, CNS has still not been reported. In this study, we investigated the distribution of GABA using immunohistochemistry. The result revealed that GABA immunoreactivity (-ir) was observed in neurons and fibres throughout the CNS, including the eyestalk, brain, and ventral nerve cord of S. olivacea. Therefore, the existence and extensive distribution pattern of GABA in the CNS of the male mud crab suggest its possible roles in feeding, locomotion, and also reproduction.

Argos and Spitz group genes function to regulate midline glial cell number in Drosophila embryos

Development ◽  
1997 ◽  
Vol 124 (19) ◽  
pp. 3787-3796 ◽  
Author(s):  
C. Stemerdink ◽  
J.R. Jacobs
Keyword(s):  
Gene Expression ◽  
Glial Cell ◽  
Nerve Cord ◽  
Egf Receptor ◽  
Ectopic Expression ◽  
Cell Number ◽  
Glia Cell ◽  
Drosophila Embryos

The midline glia of the Drosophila embryonic nerve cord undergo a reduction in cell number after facilitating commissural tract morphogenesis. The numbers of midline glia entering apoptosis at this stage can be increased by a loss or reduction of function in genes of the spitz group or Drosophila EGF receptor (DER) pathway. Argos, a secreted molecule with an atypical EGF motif, is postulated to function as a DER antagonist. In this work, we assess the role of argos in the determination of midline glia cell number. Although all midline glia express DER, argos expression is restricted to the midline glia which do not enter apoptosis. Fewer midline glia enter apoptosis in embryos lacking argos function. Ectopic expression of argos is sufficient to remove all DER-expressing midline glia from the nerve cord, even those that already express argos. DER expression is not terminated in the midline glia after spitz group signaling triggers changes in gene expression. It is therefore likely that an attenuation of DER signaling by Argos is integrated with the augmentation of DER signaling by Spitz throughout the period of reduction of midline glia number. We suggest that signaling by Spitz but not Argos is restricted to adhesive junctions. In this manner, midline glia not forming signaling junctions remain sensitive to juxtacrine Argos signaling, while an autocrine Argos signal is excluded by the adhesive junction.

scholarly journals Interdependence of macrophage migration and ventral nerve cord development in Drosophila embryos

Development ◽  
2010 ◽  
Vol 137 (10) ◽  
pp. 1625-1633 ◽  
Author(s):  
I. R. Evans ◽  
N. Hu ◽  
H. Skaer ◽  
W. Wood
Keyword(s):  
Nerve Cord ◽  
Ventral Nerve Cord ◽  
Macrophage Migration ◽  
Drosophila Embryos

scholarly journals The dynamic transmission of positional information in stau- mutants during Drosophila embryogenesis

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Zhe Yang ◽  
Hongcun Zhu ◽  
Kakit Kong ◽  
Xiaoxuan Wu ◽  
Jiayi Chen ◽  
...  
Keyword(s):  
Measurement Errors ◽  
Time Windows ◽  
Positional Information ◽  
Intensity Noise ◽  
Wild Type ◽  
Drosophila Embryogenesis ◽  
Self Organized ◽  
Short Time ◽  
Embryo Length ◽  
Drosophila Embryos

It has been suggested that Staufen (Stau) is key in controlling the variability of the posterior boundary of the Hb anterior domain (xHb). However, the mechanism that underlies this control is elusive. Here, we quantified the dynamic 3D expression of segmentation genes in Drosophila embryos. With improved control of measurement errors, we show that the xHb of stau– mutants reproducibly moves posteriorly by 10% of the embryo length (EL) to the wild type (WT) position in the nuclear cycle (nc) 14, and that its variability over short time windows is comparable to that of the WT. Moreover, for stau– mutants, the upstream Bicoid (Bcd) gradients show equivalent relative intensity noise to that of the WT in nc12–nc14, and the downstream Even-skipped (Eve) and cephalic furrow (CF) show the same positional errors as these factors in WT. Our results indicate that threshold-dependent activation and self-organized filtering are not mutually exclusive and could both be implemented in early Drosophila embryogenesis.

Morphology of programmed cell death in the ventral nerve cord of Caenorhabditis elegans larvae

Development ◽  
1982 ◽  
Vol 67 (1) ◽  
pp. 89-100
Author(s):  
Alison M. G. Robertson ◽  
J. N. Thomson
Keyword(s):  
Cell Death ◽  
Caenorhabditis Elegans ◽  
Programmed Cell Death ◽  
Ultrastructural Study ◽  
Nerve Cord ◽  
Ventral Nerve Cord ◽  
Condensed Chromatin ◽  
C Elegans ◽  
Programmed Death ◽  
Selection Of

In the nematode C. elegans, cells undergoing programmed death in the developing ventral nerve cord were identified by Nomarski optics and prepared for ultrastructural study at various times after their birth in mitosis. The sequence of changes observed suggests that the hypodermis recognizes the dying cell before completion of telophase. The dying cell is engulfed and digestion then occurs until all that remains within the hypodermal cytoplasm is a collection of membranous whorls interspersed with condensed chromatin-like remnants. The process shares several features with apoptosis, the mode of programmed cell death observed in vertebrates and insects. The selection of cells for programmed death appears not to involve competition for peripheral targets.

Enhanced haemolymph circulation by insect ventral nerve cord: hormonal control byPseudaletia unipunctaallatotropin and serotonin

2002 ◽  
Vol 205 (20) ◽  
pp. 3123-3131
Author(s):  
P. M. Koladich ◽  
S. S. Tobe ◽  
J. N. McNeil
Keyword(s):  
Nerve Cord ◽  
Ventral Nerve Cord ◽  
Dorsal Surface ◽  
Active Role ◽  
Hormonal Control ◽  
Dorsal Vessel ◽  
The Central Nervous System ◽  
True Armyworm ◽  
Tissue Matrix ◽  
Dose Dependent

SUMMARYThe ventral diaphragm (VD) in many insects is a muscular membrane that essentially partitions a perineural sinus from the rest of the abdomen. In the true armyworm moth Pseudaletia unipuncta (Lepidoptera: Noctuidae) we describe how the VD is characterized by a series of aliform muscles inserted into a tissue matrix that is fused to the dorsal surface of the ventral nerve cord (VNC) itself. Because of this arrangement, the abdominal VNC can attain high rates of lateral oscillation, and is capable of directing haemolymph flow. We have previously demonstrated Manduca sexta allatotropin(Manse-AT)-like immunoreactivity throughout the central nervous system (CNS)in P. unipuncta, and that both Manse-AT and serotonin (5-HT) are dose-dependent stimulators of the dorsal vessel. Here we describe both Manse-AT- and 5-HT-like immunoreactivity associated with the VD. Furthermore,both Manse-AT and 5-HT are dose-dependent stimulators of the rates of VNC oscillation, and together are capable of maintaining highly elevated rates of VNC oscillation for extended periods of time. These data indicate that both the dorsal vessel and the VD/VNC are similarly modulated by both Manse-AT and 5-HT, and that VNC oscillations play a more active role in overall haemolymph circulation than previously recognized.

Axon repulsion from the midline of the Drosophila CNS requires slit function

Development ◽  
1999 ◽  
Vol 126 (11) ◽  
pp. 2475-2481 ◽  
Author(s):  
R. Battye ◽  
A. Stevens ◽  
J.R. Jacobs
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Transgene Expression ◽  
Ectopic Expression ◽  
Growth Cones ◽  
Drosophila Embryogenesis ◽  
Putative Receptor ◽  
Midline Crossing ◽  
The Central Nervous System ◽  
Axon Repulsion

Guidance of axons towards or away from the midline of the central nervous system during Drosophila embryogenesis reflects a balance of attractive and repulsive cues originating from the midline. Here we demonstrate that Slit, a protein secreted by the midline glial cells provides a repulsive cue for the growth cones of axons and muscle cells. Embryos lacking slit function show a medial collapse of lateral axon tracts and ectopic midline crossing of ventral muscles. Transgene expression of slit in the midline restores axon patterning. Ectopic expression of slit inhibits formation of axon tracts at locations of high Slit production and misdirects axon tracts towards the midline. slit interacts genetically with roundabout, which encodes a putative receptor for growth cone repulsion.

scholarly journals Differential control of Yorkie activity by LKB1/AMPK and the Hippo/Warts cascade in the central nervous system

2015 ◽  
Vol 112 (37) ◽  
pp. E5169-E5178 ◽  
Author(s):  
Ieva Gailite ◽  
Birgit L. Aerne ◽  
Nicolas Tapon
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Tumor Suppressor ◽  
Nerve Cord ◽  
Ventral Nerve Cord ◽  
Tissue Growth ◽  
Binding Motif ◽  
Transcriptional Coactivator ◽  
Central Brain ◽  
The Central Nervous System

The Hippo (Hpo) pathway is a highly conserved tumor suppressor network that restricts developmental tissue growth and regulates stem cell proliferation and differentiation. At the heart of the Hpo pathway is the progrowth transcriptional coactivator Yorkie [Yki–Yes-activated protein (YAP)/transcriptional coactivator with PDZ-binding motif (TAZ) in mammals]. Yki activity is restricted through phosphorylation by the Hpo/Warts core kinase cascade, but increasing evidence indicates that core kinase-independent modes of regulation also play an important role. Here, we examine Yki regulation in the Drosophila larval central nervous system and uncover a Hpo/Warts-independent function for the tumor suppressor kinase liver kinase B1 (LKB1) and its downstream effector, the energy sensor AMP-activated protein kinase (AMPK), in repressing Yki activity in the central brain/ventral nerve cord. Although the Hpo/Warts core cascade restrains Yki in the optic lobe, it is dispensable for Yki target gene repression in the late larval central brain/ventral nerve cord. Thus, we demonstrate a dramatically different wiring of Hpo signaling in neighboring cell populations of distinct developmental origins in the central nervous system.

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