Analysis of the rds/peripherin.rom1 complex in transgenic photoreceptors that express a chimeric protein.
Mice homozygous for the retinal degeneration slow (rds) mutation completely lack photoreceptor outer segments. The rds gene encodes rds/peripherin (rds), a membrane glycoprotein in the rims of rod and cone outer segment discs. rds is present as a complex with the related protein, rom1. Here, we generated transgenic mice that express a chimeric protein (rom/D2) containing the intradiscal D2 loop of rds in the context of rom1. rom/D2 was N-glycosylated, formed covalent homodimers, and interacted non-covalently with itself, rds, and rom1. The rds.rom/D2 interaction was significantly more stable than the non-covalent interaction between rds and rom1 by detergent/urea titration. Analysis of mice expressing rom/D2 revealed that rds is 2.5-fold more abundant than rom1, interacts non-covalently with itself and rom1 via the D2 loop, and forms a high order complex that may extend the entire circumference of the disc. Expression of rom/D2 fully rescued the ultrastructural phenotype in rds+/- mutant mice, but it had no effect on the phenotype in rds-/- mutants. Together, these observations explain the striking differences in null phenotypes and frequencies of disease-causing mutations between the RDS and ROM1 genes.
Kedzierski
W
W
Center for Basic Neuroscience, Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas 75235-9111, USA.
Weng
J
J
Travis
G H
GH
D000595:Amino Acid Sequence; D000818:Animals; D019281:Dimerization; D005136:Eye Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005838:Genotype; D007381:Intermediate Filament Proteins / Q000378:metabolism*; D008562:Membrane Glycoproteins; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D051379:Mice; D008822:Mice, Transgenic; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D064531:Peripherins; D010641:Phenotype; D020419:Photoreceptor Cells, Vertebrate / Q000737:chemistry*; D011233:Precipitin Tests; D011485:Protein Binding; D011499:Protein Processing, Post-Translational; D012333:RNA, Messenger / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics*; D012160:Retina / Q000648:ultrastructure; D016415:Sequence Alignment; D059470:Tetraspanins
D005136:Eye Proteins; D007381:Intermediate Filament Proteins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D064531:Peripherins; C578996:Prph2 protein, mouse; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; C081477:Rom1 protein, mouse; D059470:Tetraspanins