The Drosophila Ras2 and Rop gene pair: a dual homology with a yeast Ras-like gene and a suppressor of its loss-of-function phenotype

Development ◽  
1993 ◽  
Vol 117 (4) ◽  
pp. 1309-1319 ◽  
Author(s):  
A. Salzberg ◽  
N. Cohen ◽  
N. Halachmi ◽  
Z. Kimchie ◽  
Z. Lev

The promoter of the Drosophila melanogaster Ras2 gene is bidirectional, regulating an additional gene oriented in the opposite polarity. The two divergently transcribed genes are only 93 bases apart and deletion analysis proved that common cis-acting elements within this promoter region are required for the transcriptional activity of both genes. We cloned the gene paired with Ras2 in the bidirectional promoter and isolated cDNAs corresponding to its mRNA. The Ras opposite (Rop) gene encodes for a 68 × 10(3) M(r) protein which shares sequence homology with the members of a novel Saccharomyces cerevisiae gene family, including the SLY1, SEC1 and VPS33 (SLP1) genes, all of which are involved in vesicle trafficking among yeast cellular compartments. A highly conserved motif in this family is also found in beta-COP, a coat protein isolated from rat Golgi-bound nonclathrin vesicles. Thus, the Rop protein may be a component of one of the vesicle trafficking pathways in Drosophila cells. The Rop gene expression during embryogenesis is restricted to the central nervous system (CNS) and the garland cells, a small group of nephrocytes that takes up waste materials from the haemolymph by endocytosis. Ras2 is also expressed in the embryonic garland cells. In postembryonic stages, the two genes are co-expressed in the larval salivary glands and the central nervous system, and in the adult CNS and reproductive systems. Interestingly, the S. cerevisiae SLY1-20 allele is a suppressor of the loss of the YPT1 gene, a ras-like gene implicated in vesicle translocation, suggesting that the two genes may interact with one another. Since Sec1p and beta-COP may also interact with small GTP-binding proteins of the ras superfamily, it is conceivable that the Rop and Ras2 gene products are not just co-expressed in common tissues, but may also functionally interact with one another in these tissues.

2021 ◽  
Vol 13 ◽  
Author(s):  
Banglian Hu ◽  
Shengshun Duan ◽  
Ziwei Wang ◽  
Xin Li ◽  
Yuhang Zhou ◽  
...  

The colony-stimulating factor 1 receptor (CSF1R) is a key tyrosine kinase transmembrane receptor modulating microglial homeostasis, neurogenesis, and neuronal survival in the central nervous system (CNS). CSF1R, which can be proteolytically cleaved into a soluble ectodomain and an intracellular protein fragment, supports the survival of myeloid cells upon activation by two ligands, colony stimulating factor 1 and interleukin 34. CSF1R loss-of-function mutations are the major cause of adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) and its dysfunction has also been implicated in other neurodegenerative disorders including Alzheimer’s disease (AD). Here, we review the physiological functions of CSF1R in the CNS and its pathological effects in neurological disorders including ALSP, AD, frontotemporal dementia and multiple sclerosis. Understanding the pathophysiology of CSF1R is critical for developing targeted therapies for related neurological diseases.


2016 ◽  
Author(s):  
◽  
Christopher M. Owens

Injuries to nerves vary in their consequences, from weakened sensation and motor function to partial or complete paralysis. In the latter case, affecting about twenty thousand Americans yearly, the injury is debilitating and results in a significant decrease in quality of life. Currently there is no effective treatment for damage to the central nervous system, in particular the spinal cord. Compared to the injuries to the central nervous system, damage in the peripheral nerves, is more common, with about sixty thousand occurrences annually. The cost of associated surgical procedures and due to loss of function is in the billions. In this thesis we present work towards the construction and testing of a fully cellular, patented nerve graft, one amongst the first of its kind. For the fabrication of the graft we are the first to employ bioprinting (either implemented through a special purpose 3D bioprinter or manually), a novel tissue engineering method rapidly gaining acceptance and utility. We first review the status of bioprinting. We then detail the fabrication process. Next we report on the testing of the graft in an in vivo animal model through electrophysiology and histology. This is followed by the introduction of a novel in vitro model, aimed at providing a fast, inexpensive and reliable method to test engineered nerve grafts. We describe our work on the optimization of the in vitro assay and then the testing of the graft using the optimized assay. We conclude with a summary of our accomplishments and make suggestions for some exciting future applications of our approach.


2001 ◽  
Vol 155 (7) ◽  
pp. 1117-1122 ◽  
Author(s):  
Greg J. Bashaw ◽  
Hailan Hu ◽  
Catherine D. Nobes ◽  
Corey S. Goodman

The key role of the Rho family GTPases Rac, Rho, and CDC42 in regulating the actin cytoskeleton is well established (Hall, A. 1998. Science. 279:509–514). Increasing evidence suggests that the Rho GTPases and their upstream positive regulators, guanine nucleotide exchange factors (GEFs), also play important roles in the control of growth cone guidance in the developing nervous system (Luo, L. 2000. Nat. Rev. Neurosci. 1:173–180; Dickson, B.J. 2001. Curr. Opin. Neurobiol. 11:103–110). Here, we present the identification and molecular characterization of a novel Dbl family Rho GEF, GEF64C, that promotes axon attraction to the central nervous system midline in the embryonic Drosophila nervous system. In sensitized genetic backgrounds, loss of GEF64C function causes a phenotype where too few axons cross the midline. In contrast, ectopic expression of GEF64C throughout the nervous system results in a phenotype in which far too many axons cross the midline, a phenotype reminiscent of loss of function mutations in the Roundabout (Robo) repulsive guidance receptor. Genetic analysis indicates that GEF64C expression can in fact overcome Robo repulsion. Surprisingly, evidence from genetic, biochemical, and cell culture experiments suggests that the promotion of axon attraction by GEF64C is dependent on the activation of Rho, but not Rac or Cdc42.


2011 ◽  
Vol 392 (8-9) ◽  
pp. 779-781 ◽  
Author(s):  
Sabrina Röseler ◽  
Kirstin Sandrock ◽  
Ingrid Bartsch ◽  
Anja Busse ◽  
Heymut Omran ◽  
...  

Abstract Septins are cytoskeletal GTP-binding proteins involved in processes characterized by active membrane movement, such as cytokinesis, vesicle trafficking and exocytosis. Most septins are expressed ubiquitously, however, some septins accumulate in particular tissues. The ubiquitous SEPT11 also shows high expression levels in the central nervous system and in platelets. Here, SEPT11 is involved in vesicle trafficking and may play a role in synaptic connectivity. Interestingly, mice that harbor a homozygous Sept11 null mutation, die in utero. From day 11.5 post coitum onwards, development of homozygous embryos seems to be retarded and the embryos from day 13.5 onwards were dead.


1908 ◽  
Vol 54 (225) ◽  
pp. 146-148
Author(s):  
William W. Ireland

Rothmann points out how important it is to surgeons that the localisation of lesions in the brain and spinal cord should be made with the utmost accuracy. In many cases diseases do not strike suddenly upon a nervous system previously intact. Often the circulation has been previously deranged by arterial sclerosis, which prepares the way for transitory hemiplegia or aphasia. Sometimes there is loss of function after central lesions, which disappears in longer or shorter time. Goltz and his followers have treated many effects following the extirpation of the whole or part of the cerebrum as due to what they call inhibition (Hemmung). Thus the functions of the spinal cord are much impaired after removal of the cerebral ganglia, or the lower portion of the cord loses its reflex function after section higher up, but after a while it again resumes its act$ibon.


Development ◽  
2002 ◽  
Vol 129 (18) ◽  
pp. 4193-4203 ◽  
Author(s):  
Marita Buescher ◽  
Fook Sion Hing ◽  
William Chia

Sox proteins form a family of HMG-box transcription factors related to the mammalian testis determining factor SRY. Sox-mediated modulation of gene expression plays an important role in various developmental contexts. Drosophila SoxNeuro, a putative ortholog of the vertebrate Sox1, Sox2 and Sox3 proteins, is one of the earliest transcription factors to be expressed pan-neuroectodermally. We demonstrate that SoxNeuro is essential for the formation of the neural progenitor cells in central nervous system. We show that loss of function mutations of SoxNeuro are associated with a spatially restricted hypoplasia: neuroblast formation is severely affected in the lateral and intermediate regions of the central nervous system, whereas ventral neuroblast formation is almost normal. We present evidence that a requirement for SoxNeuro in ventral neuroblast formation is masked by a functional redundancy with Dichaete, a second Sox protein whose expression partially overlaps that of SoxNeuro. Genetic interactions of SoxNeuro and the dorsoventral patterning genes ventral nerve chord defective and intermediate neuroblasts defective underlie ventral and intermediate neuroblast formation. Finally, the expression of the Achaete-Scute gene complex suggests that SoxNeuro acts upstream and in parallel with the proneural genes.


Development ◽  
1995 ◽  
Vol 121 (11) ◽  
pp. 3549-3560 ◽  
Author(s):  
J.F. Emery ◽  
E. Bier

The Drosophila pan-neural genes deadpan (dpn) and scratch (scrt) are expressed in most or all developing neural precursor cells of the central nervous system (CNS) and peripheral nervous system (PNS). We have identified a cis-acting enhancer element driving full pan-neural expression of the dpn gene which is composed of independent CNS- and PNS-specific subelements. We have also identified CNS- and PNS-specific subelements of the scrt enhancer. Deletion analysis of the dpn and scrt PNS-specific subelements reveals that PNS specificity of these two evolutionarily unrelated enhancers is achieved in part by repression of CNS expression. We discuss the implications of the striking organizational similarities of the dpn, scrt, and sna pan-neural enhancers.


2011 ◽  
Vol 91 (2) ◽  
pp. 461-553 ◽  
Author(s):  
Helmut Kettenmann ◽  
Uwe-Karsten Hanisch ◽  
Mami Noda ◽  
Alexei Verkhratsky

Microglial cells are the resident macrophages in the central nervous system. These cells of mesodermal/mesenchymal origin migrate into all regions of the central nervous system, disseminate through the brain parenchyma, and acquire a specific ramified morphological phenotype termed “resting microglia.” Recent studies indicate that even in the normal brain, microglia have highly motile processes by which they scan their territorial domains. By a large number of signaling pathways they can communicate with macroglial cells and neurons and with cells of the immune system. Likewise, microglial cells express receptors classically described for brain-specific communication such as neurotransmitter receptors and those first discovered as immune cell-specific such as for cytokines. Microglial cells are considered the most susceptible sensors of brain pathology. Upon any detection of signs for brain lesions or nervous system dysfunction, microglial cells undergo a complex, multistage activation process that converts them into the “activated microglial cell.” This cell form has the capacity to release a large number of substances that can act detrimental or beneficial for the surrounding cells. Activated microglial cells can migrate to the site of injury, proliferate, and phagocytose cells and cellular compartments.


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