The role of Slit-Robo signaling in the generation, migration and morphological differentiation of cortical interneurons

AbstractExplicitly accounting for phenotypic differentiation together with environmental heterogeneity is crucial to understand the evolutionary dynamics in hybrid zones. Species showing intra-specific variation in phenotypic traits that meet across environmentally heterogeneous regions constitute excellent natural settings to study the role of phenotypic differentiation and environmental factors in shaping the spatial extent and patterns of admixture in hybrid zones. We studied three environmentally distinct contact zones where morphologically and reproductively divergent subspecies of Salamandra salamandra co-occur: the pueriparous S. s. bernardezi that is mostly parapatric to its three larviparous subspecies neighbours. We used a landscape genetics framework to: (i) characterise the spatial location and extent of each contact zone; (ii) assess patterns of introgression and hybridization between subspecies pairs; and (iii) examine the role of environmental heterogeneity in the evolutionary dynamics of hybrid zones. We found high levels of introgression between parity modes, and between distinct phenotypes, thus demonstrating the evolution to pueriparity alone or morphological differentiation do not lead to reproductive isolation between these highly divergent S. salamandra morphotypes. However, we detected substantial variation in patterns of hybridization across contact zones, being lower in the contact zone located on a topographically complex area. We highlight the importance of accounting for spatial environmental heterogeneity when studying evolutionary dynamics of hybrid zones.

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Role of Somatostatin-Positive Cortical Interneurons in the Generation of Sleep Slow Waves

Journal of Neuroscience ◽

10.1523/jneurosci.1303-17.2017 ◽

2017 ◽

Vol 37 (38) ◽

pp. 9132-9148 ◽

Cited By ~ 46

Author(s):

Chadd M. Funk ◽

Kayla Peelman ◽

Michele Bellesi ◽

William Marshall ◽

Chiara Cirelli ◽

...

Keyword(s):

Slow Waves ◽

Cortical Interneurons

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Calretinin expression in the mammalian neocortex: a review

Physiological Research ◽

10.33549/physiolres.931930 ◽

2010 ◽

pp. 665-677

Author(s):

F Barinka ◽

R Druga

Keyword(s):

Calcium Binding ◽

Binding Protein ◽

Calcium Binding Protein ◽

Actual Knowledge ◽

Neuronal Homeostasis ◽

Physiological Properties ◽

Cortical Interneurons

In the mammalian neocortex, the calcium-binding protein calretinin is expressed in a subset of cortical interneurons. In the recent years, research on interneurons is one of the most rapidly growing fields in neuroscience. This review summarizes the actual knowledge of the functions of calretinin in neuronal homeostasis and particularly of the distribution, connectivity and physiological properties of calretinin expressing interneurons in the neocortex of rodents and primates, including humans. The possible neuroprotective role of calretinin and the presumed “resistance” of calretinin-expressing interneurons to various pathological processes are also discussed.

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Key aspects of neurovascular control mediated by specific populations of inhibitory cortical interneurons

10.1101/550269 ◽

2019 ◽

Author(s):

L Lee ◽

L Boorman ◽

E Glendenning ◽

C Christmas ◽

P Sharp ◽

...

Keyword(s):

Neural Activity ◽

Cortical Inhibition ◽

Cortical Interneurons ◽

Haemodynamic Changes ◽

A Cell ◽

Cortical Excitation ◽

Negative Bold ◽

Key Aspects ◽

Oxide Synthase

AbstractInhibitory interneurons can evoke vasodilation and vasoconstriction, making them potential cellular drivers of neurovascular coupling. However, the specific regulatory roles played by particular interneuron subpopulations remain unclear. Our purpose was therefore to adopt a cell-specific optogenetic approach to investigate how somatostatin (SST) and neuronal nitric oxide synthase (NOS1)-expressing interneurons might influence neurovascular relationships. In mice, specific activation of SST- or NOS1-interneurons was sufficient to evoke haemodynamic changes similar to those evoked by physiological whisker stimulation. In the case of NOS1-interneurons, robust haemodynamic changes occurred with minimal changes in neural activity. Conversely, activation of SST-interneurons produced robust changes in evoked neural activity with shallow cortical excitation and pronounced deep layer cortical inhibition. This often resulted in a central increase in blood volume with corresponding surround decrease, analogous to the negative BOLD signal. These results demonstrate the role of specific populations of cortical interneurons in the active control of neurovascular function.

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Initiation and maintenance of NGF-stimulated neurite outgrowth requires activation of a phosphoinositide 3-kinase

Journal of Cell Science ◽

10.1242/jcs.109.2.289 ◽

1996 ◽

Vol 109 (2) ◽

pp. 289-300 ◽

Cited By ~ 3

Author(s):

T.R. Jackson ◽

I.J. Blader ◽

L.P. Hammonds-Odie ◽

C.R. Burga ◽

F. Cooke ◽

...

Keyword(s):

Neurite Outgrowth ◽

Pc12 Cells ◽

Specific Inhibitor ◽

Morphological Differentiation ◽

Sympathetic Neuron ◽

Neuronal Morphology ◽

Regulatory Subunit ◽

Membrane Reorganization ◽

Phosphoinositide 3 Kinase

Application of nerve growth factor (NGF) to PC12 cells stimulates a programme of physiological changes leading to the development of a sympathetic neuron like phenotype, one aspect of which is the development of a neuronal morphology characterised by the outgrowth of neuritic processes. We have investigated the role of phosphoinositide 3-kinase in NGF-stimulated morphological differentiation through two approaches: firstly, preincubation with wortmannin, a reputedly specific inhibitor of phosphoinositide kinases, completely inhibited initial morphological responses to NGF, the formation of actin filament rich microspikes and subsequent neurite outgrowth. This correlated with wortmannin inhibition of NGF-stimulated phosphatidylinositol(3,4,5)trisphosphate (PtdInsP3) and phosphatidylinositol(3,4)bisphosphate (PtdIns(3,4)P2) production and with inhibition of NGF-stimulated phosphoinositide 3-kinase activity in anti-phosphotyrosine immunoprecipitates. Secondly, the overexpression of a mutant p85 regulatory subunit of the phosphoinositide 3-kinase, which cannot interact with the catalytic p110 subunit, also substantially inhibited the initiation of NGF-stimulated neurite outgrowth. In addition, we found that wortmannin caused a rapid collapse of more mature neurites formed following several days exposure of PC12 cells to NGF. These results indicate that NGF-stimulated neurite outgrowth requires the activity of a tyrosine kinase regulated PI3-kinase and suggest that the primary product of this enzyme, PtdInsP3, is a necessary second messenger for the cytoskeletal and membrane reorganization events which occur during neuronal differentiation.

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The novel ECF56 SigG1-RsfG system modulates morphological differentiation and metal-ion homeostasis in Streptomyces tsukubaensis

Scientific Reports ◽

10.1038/s41598-020-78520-x ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Rute Oliveira ◽

Matthew J. Bush ◽

Sílvia Pires ◽

Govind Chandra ◽

Delia Casas-Pastor ◽

...

Keyword(s):

Metal Ion ◽

Ion Homeostasis ◽

Morphological Differentiation ◽

The Novel ◽

Copper Trafficking ◽

Streptomyces Tsukubaensis ◽

Metal Ion Homeostasis ◽

Σ Factor ◽

Domain Organisation

AbstractExtracytoplasmic function (ECF) sigma factors are key transcriptional regulators that prokaryotes have evolved to respond to environmental challenges. Streptomyces tsukubaensis harbours 42 ECFs to reprogram stress-responsive gene expression. Among them, SigG1 features a minimal conserved ECF σ2–σ4 architecture and an additional C-terminal extension that encodes a SnoaL_2 domain, which is characteristic for ECF σ factors of group ECF56. Although proteins with such domain organisation are widely found among Actinobacteria, the functional role of ECFs with a fused SnoaL_2 domain remains unknown. Our results show that in addition to predicted self-regulatory intramolecular amino acid interactions between the SnoaL_2 domain and the ECF core, SigG1 activity is controlled by the cognate anti-sigma protein RsfG, encoded by a co-transcribed sigG1-neighbouring gene. Characterisation of ∆sigG1 and ∆rsfG strains combined with RNA-seq and ChIP-seq experiments, suggests the involvement of SigG1 in the morphological differentiation programme of S. tsukubaensis. SigG1 regulates the expression of alanine dehydrogenase, ald and the WhiB-like regulator, wblC required for differentiation, in addition to iron and copper trafficking systems. Overall, our work establishes a model in which the activity of a σ factor of group ECF56, regulates morphogenesis and metal-ions homeostasis during development to ensure the timely progression of multicellular differentiation.

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