The retinitis pigmentosa GTPase regulator (RPGR) interacts with novel transport-like proteins in the outer segments of rod photoreceptors.
Mutations in the retinitis pigmentosa GTPase regulator (RPGR) gene cause X-linked retinitis pigmentosa type 3 (RP3), a severe, progressive and degenerative retinal dystrophy eventually leading to complete blindness. RPGR is ubiquitously expressed, yet mutations in the RPGR gene lead to a retina-restricted phenotype. To date, all RP3 associated missense mutations ... that have been identified are located in the RCC1-homologous domain (RHD) of RPGR. To investigate the molecular pathogenesis of RP3, we screened retinal yeast two-hybrid libraries with the RHD of RPGR. We identified several alternatively spliced gene products, some with retina-restricted expression, that interact specifically with RPGR in vivo and in vitro. Thus, these proteins were named RPGR-interacting protein 1 (RPGRIP1) isoforms. They contain a C-terminal RPGR-interacting domain and stretches of variable coiled-coil domains homologous to proteins involved in vesicular trafficking. The interaction between RPGR and RPGRIP1 isoforms was impaired in vivo by RP3-associated mutations in RPGR. Moreover, RPGR and RPGRIP1 co-localize in the outer segment of rod photoreceptors, which is in full agreement with the retinitis pigmentosa phenotype observed in RP3 patients. The localization of RPGRIP1 at 14q11 makes it a strong candidate gene for RP16. These results provide a clue for the retina-specific pathogenesis in RP3, and hint towards the involvement of RPGR and RPGRIP1 in mediating vesicular transport-associated processes.
Mesh Terms:
3' Untranslated Regions, Alternative Splicing, Amino Acid Sequence, Animals, Blotting, Northern, Blotting, Western, Carrier Proteins, Cattle, Cell-Free System, Chromosomes, Human, Pair 14, Eye Proteins, Glutathione Transferase, Humans, Immunohistochemistry, Models, Genetic, Molecular Sequence Data, Mutation, Mutation, Missense, Phenotype, Plasmids, Precipitin Tests, Protein Biosynthesis, Protein Isoforms, Protein Structure, Tertiary, Proteins, Retina, Retinal Rod Photoreceptor Cells, Reverse Transcriptase Polymerase Chain Reaction, Sequence Homology, Amino Acid, Temperature, Tissue Distribution, Transcriptional Activation, Two-Hybrid System Techniques
3' Untranslated Regions, Alternative Splicing, Amino Acid Sequence, Animals, Blotting, Northern, Blotting, Western, Carrier Proteins, Cattle, Cell-Free System, Chromosomes, Human, Pair 14, Eye Proteins, Glutathione Transferase, Humans, Immunohistochemistry, Models, Genetic, Molecular Sequence Data, Mutation, Mutation, Missense, Phenotype, Plasmids, Precipitin Tests, Protein Biosynthesis, Protein Isoforms, Protein Structure, Tertiary, Proteins, Retina, Retinal Rod Photoreceptor Cells, Reverse Transcriptase Polymerase Chain Reaction, Sequence Homology, Amino Acid, Temperature, Tissue Distribution, Transcriptional Activation, Two-Hybrid System Techniques
Hum. Mol. Genet.
Date: Sep. 01, 2000
PubMed ID: 10958648
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