Developmental control of rod number via a light-dependent retrograde pathway from intrinsically photosensitive retinal ganglion cells.

Photoreception is essential for the development of the visual system, shaping vision's first synapse to cortical development. Here, we find that the lighting environment controls developmental rod apoptosis via Opn4-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs). Using genetics, sensory environment manipulations, and computational approaches, we establish a pathway where light-dependent glutamate released from ipRGCs is detected via a transiently expressed glutamate receptor (Grik3) on rod precursors within the inner retina.

Comprehensive Behavioral Analysis of Opsin 3 (Encephalopsin)-Deficient Mice Identifies Role in Modulation of Acoustic Startle Reflex.

Opsin-3 (, encephalopsin) was the first nonvisual opsin gene discovered in mammals. Since then, several functions have been described, and in two cases (adipose tissue, smooth muscle) light sensing activity is implicated. In addition to peripheral tissues, is robustly expressed within the central nervous system, for which it derives its name.

Violet-light suppression of thermogenesis by opsin 5 hypothalamic neurons.

The opsin family of G-protein-coupled receptors are used as light detectors in animals. Opsin 5 (also known as neuropsin or OPN5) is a highly conserved opsin that is sensitive to visible violet light. In mice, OPN5 is a known photoreceptor in the retina and skin but is also expressed in the hypothalamic preoptic area (POA).

Adaptive Thermogenesis in Mice Is Enhanced by Opsin 3-Dependent Adipocyte Light Sensing.

Almost all life forms can detect and decode light information for adaptive advantage. Examples include the visual system, in which photoreceptor signals are processed into virtual images, and the circadian system, in which light entrains a physiological clock. Here we describe a light response pathway in mice that employs encephalopsin (OPN3, a 480 nm, blue-light-responsive opsin) to regulate the function of adipocytes.

An opsin 5-dopamine pathway mediates light-dependent vascular development in the eye.

During mouse postnatal eye development, the embryonic hyaloid vascular network regresses from the vitreous as an adaption for high-acuity vision. This process occurs with precisely controlled timing. Here, we show that opsin 5 (OPN5; also known as neuropsin)-dependent retinal light responses regulate vascular development in the postnatal eye.

Developmental vascular regression is regulated by a Wnt/β-catenin, MYC and CDKN1A pathway that controls cell proliferation and cell death.

Normal development requires tight regulation of cell proliferation and cell death. Here, we have investigated these control mechanisms in the hyaloid vessels, a temporary vascular network in the mammalian eye that requires a Wnt/β-catenin response for scheduled regression. We investigated whether the hyaloid Wnt response was linked to the oncogene , and the cyclin-dependent kinase inhibitor CDKN1A (P21), both established regulators of cell cycle progression and cell death.

Molecular genetics of MARVELD2 and clinical phenotype in Pakistani and Slovak families segregating DFNB49 hearing loss.

Pathogenic mutations of MARVELD2, encoding tricellulin, a tricelluar tight junction protein, cause autosomal recessive non-syndromic hearing loss (DFNB49) in families of Pakistan and Czech Roma origin. In fact, they are a significant cause of prelingual hearing loss in the Czech Roma, second only to GJB2 variants. Previously, we reported that mice homozygous for p.

Aurora A and Aurora B jointly coordinate chromosome segregation and anaphase microtubule dynamics.

We established a conditional deletion of Aurora A kinase (AurA) in Cdk1 analogue-sensitive DT40 cells to analyze AurA knockout phenotypes after Cdk1 activation. In the absence of AurA, cells form bipolar spindles but fail to properly align their chromosomes and exit mitosis with segregation errors. The resulting daughter cells exhibit a variety of phenotypes and are highly aneuploid.

Evidence for multiple, developmentally regulated isoforms of Ptprq on hair cells of the inner ear.

Ptprq is a receptor-like inositol lipid phosphatase associated with the shaft connectors of hair bundles. Three lines of evidence suggest Ptprq is a chondroitin sulfate proteoglycan: (1) chondroitinase ABC treatment causes a loss of the ruthenium-red reactive, electron-dense particles associated with shaft connectors, (2) chondroitinase ABC causes an increase in the electrophoretic mobility of Ptprq, and (3) hair bundles in the developing inner ear of wild-type mice, but not those of Ptprq(-/-) mice, react with monoclonal antibody (mAb) 473-HD, an IgM that recognizes the dermatan-sulfate-dependent epitope DSD1. Two lines of evidence indicate that there may be multiple isoforms of Ptprq expressed in hair bundles.

Development of the hair bundle and mechanotransduction.

This review focuses on the cellular and molecular mechanisms underlying the development of the sensory hair bundle, an apical specialisation of the hair cell that is essential for mechanotransduction. The structure, function and development of the hair bundle is described, with an emphasis on the properties and possible roles played by the different link types that interconnect the individual elements of the hair bundle - the multiple stereocilia and the single kinocilium. Studies of mouse and zebrafish mutants have revealed that several classes of molecule are required for the genesis and maintenance of hair-bundle structure.