Unusual congenital demyelinating neuropathies with sensory organ deficits caused by mutant transcription factors

Inner ear formation requires that a series of cell fate decisions and morphogenetic events occur in a precise temporal and spatial pattern. Previous studies have shown that transcription factors, including Pax2, Sox2, and Prox1, play important roles during the inner ear development. However, the temporospatial expression patterns among these transcription factors are poorly understood. In the current study, we present a comprehensive description of the temporal and spatial expression profiles of Pax2, Sox2, and Prox1 during auditory and vestibular sensory organ development in mice. Using immunohistochemical analyses, we show that Sox2 and Pax2 are both expressed in the prosensory cells (the developing hair cells), but Sox2 is later restricted to only the supporting cells of the organ of Corti. In the vestibular sensory organ, however, the Pax2 expression is localized in hair cells at postnatal day 7, while Sox2 is still expressed in both the hair cells and supporting cells at that time. Prox1 was transiently expressed in the presumptive hair cells and developing supporting cells, and lower Prox1 expression was observed in the vestibular sensory organ compared to the organ of Corti. The different expression patterns of these transcription factors in the developing auditory and vestibular sensory organs suggest that they play different roles in the development of the sensory epithelia and might help to shape the respective sensory structures.

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Drosophila Hören: Mechanismen und Gene

e-Neuroforum ◽

10.1515/nf-2014-0306 ◽

2014 ◽

Vol 20 (3) ◽

Author(s):

Maike Kittelmann ◽

Martin Göpfert

Keyword(s):

Drosophila Melanogaster ◽

Transcription Factors ◽

Ion Channels ◽

Hair Cells ◽

Motor Proteins ◽

Fruit Fly ◽

Sensory Organ ◽

Sensory Cells ◽

Mechanical Vibrations ◽

Signalling Cascades

AbstractDrosophila hearing: mechanisms and genes.The fruit fly Drosophila melanogaster communicates acoustically and hears with its antennae. Fundamental aspects of hearing can be studied in these antennal ears. Their auditory sensory cells are evolutionarily related with vertebrate hair cells and are developmentally specified by homologous transcription factors. Like vertebrate hair cells, Drosophila auditory sensory cells are also motile and actively amplify the mechanical vibrations that they transduce. This transduction and amplification rely on the interplay between mechanically activated ion channels and motor proteins, whose movement impacts on the macroscopic performance of the ear. First molecular transducer components have been identified and various auditory relevant proteins have been described. Several of these proteins are conserved components of cilia, putting forward the fly’s ear as a model for human ciliopathies. Also the evolution of sensory signalling cascades can be studied using the fly’s ear as the fly employs key Chemo-and Photoreceptor proteins to hear. Evidence is also accumulating that the fly’s ear is a multifunctional sensory organ that, in addition to mediating hearing, serves the detection of wind and gravity and, presumably, temperature.

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Functional analysis of sense organ specification in the Tribolium castaneum larva reveals divergent mechanisms in insects

BMC Biology ◽

10.1186/s12915-021-00948-y ◽

2021 ◽

Vol 19 (1) ◽

Author(s):

Marleen Klann ◽

Magdalena Ines Schacht ◽

Matthew Alan Benton ◽

Angelika Stollewerk

Keyword(s):

Gene Expression ◽

Transcription Factors ◽

Tribolium Castaneum ◽

Dominant Role ◽

Sense Organ ◽

Past Research ◽

Cell Types ◽

Sensory Organ ◽

Sense Organs ◽

Evolutionary Scenario

Abstract Insects and other arthropods utilise external sensory structures for mechanosensory, olfactory, and gustatory reception. These sense organs have characteristic shapes related to their function, and in many cases are distributed in a fixed pattern so that they are identifiable individually. In Drosophila melanogaster, the identity of sense organs is regulated by specific combinations of transcription factors. In other arthropods, however, sense organ subtypes cannot be linked to the same code of gene expression. This raises the questions of how sense organ diversity has evolved and whether the principles underlying subtype identity in D. melanogaster are representative of other insects. Here, we provide evidence that such principles cannot be generalised, and suggest that sensory organ diversification followed the recruitment of sensory genes to distinct sensory organ specification mechanism. Results We analysed sense organ development in a nondipteran insect, the flour beetle Tribolium castaneum, by gene expression and RNA interference studies. We show that in contrast to D. melanogaster, T. castaneum sense organs cannot be categorised based on the expression or their requirement for individual or combinations of conserved sense organ transcription factors such as cut and pox neuro, or members of the Achaete-Scute (Tc ASH, Tc asense), Atonal (Tc atonal, Tc cato, Tc amos), and neurogenin families (Tc tap). Rather, our observations support an evolutionary scenario whereby these sensory genes are required for the specification of sense organ precursors and the development and differentiation of sensory cell types in diverse external sensilla which do not fall into specific morphological and functional classes. Conclusions Based on our findings and past research, we present an evolutionary scenario suggesting that sense organ subtype identity has evolved by recruitment of a flexible sensory gene network to the different sense organ specification processes. A dominant role of these genes in subtype identity has evolved as a secondary effect of the function of these genes in individual or subsets of sense organs, probably modulated by positional cues.

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