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Rachel Drake, University of Minnesota Jennifer Phillips, University of Oregon Westerfield Lab M. Pyron, 2003 1
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Overview I.Introduction to Usher syndrome II. Experimental Approach III. Results IV. Future Directions 2
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Autosomal recessive syndrome Causes deafblindness Clinically variable presentation Usher syndrome 3
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Usher type IUsher type IIUsher type III Visual Impairment Onset in early childhood Onset in late childhood Variable Hearing Impairment Congenital ProfoundCongenital Moderate/ Severe Progressive Variable Balance Defect PresentAbsentVariable More Severe Less Severe 4
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Progressive photoreceptor degeneration Congenital moderate hearing loss Caused by mutation of the USH2A gene which encodes the protein Usherin Most common subtype of Usher syndrome 5
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Adato et. Al, 2005 Human Molecular Genetics Thrombospondin-type laminin G domain Transmembrane domain PDZ – domain binding motif 10205030406070 7
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Eye: Photoreceptors Ear: Hair cells 1. Nascone, 2007 2. J. Phillips 1 2 8dpf 5dpf 8
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http://webvision.med.utah.edu http://what-when-how.com/acp-medicine/the-dizzy-patient-part-1 Retina Hair cells 9
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I. Introduction to Usher syndrome II. Experimental Approach III. Results IV. Future Directions 10
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11 Thrombospondin-type laminin G domain Transmembrane domain PDZ – domain binding motif Exon 4 Exon 69 introns AAAAA Unprocessed mRNA transcript:
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C. Rouzer, 2010 GCCATAGCTAGCAATCGA ATCG Exon 69Intron 69 Example Morpholino injection: 12
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2d WT 6d WT3d WT6d E693d E69 2d E69 Ladder Results: E4 and E69 Morpholinos appear to specifically alter ush2a transcripts Jen Phillips, Jeremy Wegner E4 morphant fragments E69 Morphant fragments 8d WT 8d E4 1Kb Ladder 500 bp 13
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Usherin is present in hair cells of uninjected fish through 5dpf 14 2dpf4dpf ac tub usherin 3dpf 5dpf ac tub usherin
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Usherin is reduced in E69 Morphant Hair cells through 4 dpf 3dpf 4dpf 2dpf Wild-TypeE69 Morphant 15 ac tub usherin ac tub usherin
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is present in retina of uninjected fish through 4dpf 16 2 dpf 3 dpf 4 dpf ac tub usherin
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Disruption of splicing at exon 4 causes depletion of in photoreceptors at 5 dpf: 17 ac tub usherin Wild-typeE4 morphant
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is depleted in retina of E69 morphant through 4dpf 18 E69 morphantWild-type 2 dpf 3 dpf 4 dpf ac tub usherin
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8 dpf, E4 morphant Previously shown: Average Number of Labeled Photoreceptors in E4 morphant at 5dpf Uninjected Control.05±0.22 ush2aMO (E4)2.75±1.3 *** p<0.0001 Eberman et. al 2010 19 Caspase-3
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20 p<0.0001
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Conclusions E4 and E69 morpholinos appear to specifically alter ush2a transcript 21 E4 and E69 morpholinos achieve a similar level of protein depletion in retina and hair cells. Photoreceptor cell death in morphants appears to phenocopy the retinal degeneration of Usher syndrome.
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I.Introduction to Usher syndrome II. Experimental Approach III. Results IV. Future Directions 22
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Future Directions Determine exactly how the transcript is altered. 23
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Ush2aUsh2cUsh2d Ac tub 24 Ush2db Ush2c Ush2da Ush2a Determine interdependence of Usher type II proteins:
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25 Ush2d Ush 2c Ush 2a ?
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26 Jennifer Phillips Monte Westerfield Sabrina Toro Jeremy Wegner Judy Peirce Aurélie Clément Bernardo Blanco Peter O’Day Adam Unger Jennifer Panlilio Nicole Villegas Dylan Calame Marcel Rockwell NIH-1R25HD070817 NICHD Summer Research Program at the University of Oregon NICHD
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