Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

NRL (neural retina leucine zipper) is a basic motif leucine zipper transcription factor of the Maf-subfamily. Multiple phosphorylated isoforms of NRL are detected specifically in rod photoreceptors. NRL regulates the expression of several rod-specific genes, including rhodopsin and cGMP phosphodiesterase beta-subunit, in synergy with other transcription factors (e.g. the homeodomain protein CRX). Missense mutations in the human NRL gene are associated with autosomal dominant retinitis pigmentosa, whereas the loss of its function leads to rodless retina in Nrl-knockout mice that exhibit enhanced S-cone function. To further elucidate the molecular mechanism(s) underlying NRL-mediated transcriptional regulation, we used yeast two-hybrid screening to isolate NRL-interacting proteins in the retina and report the identification of Flt3-interacting zinc-finger protein, Fiz1. Interaction of Fiz1 and NRL-leucine zipper was validated by GST pulldown assays and co-immunoprecipitation from bovine retinal nuclear extracts. Fiz1 suppressed NRL- but not CRX-mediated transactivation of rhodopsin promoter activity in transiently transfected CV1 cells. The mRNA and the protein for both Fiz1 and its only other known interacting protein Flt3, a receptor tyrosine kinase, are expressed in the retina. Our results indicate potential cross-talk among signaling pathways in the retina and suggest that the function of NRL is modulated by its interaction with specific repressor proteins.
Hum Mol Genet 2003 Feb 15
PMID:Interaction of retinal bZIP transcription factor NRL with Flt3-interacting zinc-finger protein Fiz1: possible role of Fiz1 as a transcriptional repressor. 1256 83

We previously described chimeric recombinant adeno-associated virus (rAAV) vectors 2/4 and 2/5 as the most efficient vectors in rat retina. We now characterize these two vectors carrying the CMV.gfp genome following subretinal injection in the Wistar rat, beagle dog, and cynomolgus macaque. Both serotypes displayed stable GFP expression for the duration of the experiment (6 months) in all three animal models. Similar to the AAV-2 serotype, AAV-2/5 transduced both RPE and photoreceptor cells, with higher level of transduction in photoreceptors, whereas rAAV-2/4 transduction was unambiguously restricted to RPE cells. This unique specificity found conserved among all three species makes AAV-2/4-derived vectors attractive for retinal diseases originating in RPE such as Leber congenital amaurosis (RPE65) or retinitis pigmentosa due to a mutated mertk gene. To provide further important preclinical data, vector shedding was monitored by PCR in various biological fluids for 2 months post-rAAV administration. Following rAAV-2/4 and -5 subretinal delivery in dogs (n = 6) and in nonhuman primates (n = 2), vector genome was found in lacrymal and nasal fluids for up to 3-4 days and in the serum for up to 15-20 days. Overall, these findings will have a practical impact on the development of future gene therapy trials of retinal diseases.
Mol Ther 2003 Jun
PMID:Recombinant adeno-associated virus serotype 4 mediates unique and exclusive long-term transduction of retinal pigmented epithelium in rat, dog, and nonhuman primate after subretinal delivery. 1278 51

Herpes simplex virus (HSV) entry into cells requires the binding of glycoprotein D (gD) to one of several cell surface receptors. The crystal structure of gD bound to one of these receptors, HveA/HVEM, reveals that the core of gD comprises an immunoglobulin fold flanked by a long C-terminal extension and an N-terminal hairpin loop. HveA is a member of the tumor necrosis factor receptor family and contains four cysteine-rich domains (CRDs) characteristic of this family. Fourteen amino acids within the gD N-terminal loop comprise the entire binding site for HveA. To determine the contribution of each gD contact residue to virus entry, we constructed gD molecules mutated in these amino acids. We determined the abilities of the gD mutants to bind receptors, facilitate virus entry, and mediate cell-cell fusion. Seven of the gD mutants exhibited wild-type levels of receptor binding and gD function. Results from the other seven gD mutants revealed three critical regions at the gD-HveA interface. (i) Several gD residues that participate in an intermolecular beta-sheet with HveA were found to be crucial for HveA binding and entry into HveA-expressing cells. (ii) Two gD residues that contact HveA-Y23 contributed to HveA binding but were not required for mediating entry into cells. HveA-Y23 fits into a crevice on the surface of gD and was previously shown to be essential for gD binding. (iii) CRD2 was previously shown to contribute to gD binding, and this study shows that one gD residue that contacts CRD2 contributes to HveA binding. None of the gD mutations prevented interaction with nectin-1, another gD receptor. However, when cotransfected with the other glycoproteins required for fusion, two gD mutants gained the ability to mediate fusion of cells expressing nectin-2, a gD receptor that interacts with several laboratory-derived gD mutants but not with wild-type gD. Thus, results from this panel of gD mutants as well as those of previous studies (A. Carfi, S. H. Willis, J. C. Whitbeck, C. Krummenacher, G. H. Cohen, R. J. Eisenberg, and D. C. Wiley, Mol. Cell 8:169-179, 2001, and S. A. Connolly, D. J. Landsburg, A. Carfi, D. C. Wiley, R. J. Eisenberg, and G. H. Cohen, J. Virol. 76:10894-10904, 2002) provide a detailed picture of the gD-HveA interface and the contacts required for functional interaction. The results demonstrate that of the 35 gD and HveA contact residues that comprise the gD-HveA interface, only a handful are critical for complex formation.
 ...
PMID:Structure-based mutagenesis of herpes simplex virus glycoprotein D defines three critical regions at the gD-HveA/HVEM binding interface. 1282 51

Lung surfactant protein D (SP-D) can directly interact with carbohydrate residues on pulmonary pathogens and allergens, stimulate immune cells, and manipulate cytokine and chemokine profiles during the immune response in the lungs. Therapeutic administration of rfhSP-D, a recombinant homotrimeric fragment of human SP-D comprising the alpha-helical coiled-coil neck plus three CRDs, protects mice against lung allergy and infection caused by the fungal pathogen Aspergillus fumigatus. The high resolution crystal structures of maltose-bound rfhSP-D to 1.4A, and of rfhSP-D to 1.6A, define the fine detail of the mode and nature of carbohydrate recognition and provide insights into how a small fragment of human SP-D can bind to allergens/antigens or whole pathogens, and at the same time recruit and engage effector cells and molecules of humoral immunity. A previously unreported calcium ion, located on the trimeric axis in a pore at the bottom of the funnel formed by the three CRDs and close to the neck-CRD interface, is coordinated by a triad of glutamate residues which are, to some extent, neutralised by their interactions with a triad of exposed lysine residues in the funnel. The spatial relationship between the neck and the CRDs is maintained internally by these lysine residues, and externally by a glutamine, which forms a pair of hydrogen-bonds within an external cleft at each neck-CRD interface. Structural links between the central pore and the cleft suggest a possible effector mechanism for immune cell surface receptor binding in the presence of bound, extended natural lipopolysaccharide and phospholipid ligands. The structural requirements for such an effector mechanism, involving both the trimeric framework for multivalent ligand binding and recognition sites formed from more than one subunit, are present in both native hSP-D and rfhSP-D, providing a possible explanation for the significant biological activity of rfhSP-D.
J Mol Biol 2003 Aug 08
PMID:High-resolution structural insights into ligand binding and immune cell recognition by human lung surfactant protein D. 1288 56

In the Royal College of Surgeons (RCS) rat, the retinal pigment epithelium (RPE) cannot phagocytose the outer segment discs that are continually shed from photoreceptors. The resulting accumulation of debris in the subretinal space leads to a progressive loss of photoreceptors. The defect results from a mutation in the Mertk gene, which is normally expressed in the RPE. Mertk is a receptor tyrosine kinase, involved in the binding of photoreceptor debris. Mutations in MERTK have also been described in patients with retinitis pigmentosa (RP). Here we demonstrate that subretinal injection of recombinant adeno-associated virus (AAV) expressing the murine Mertk gene can significantly prolong photoreceptor cell survival in the RCS rat. Electroretinographic analysis of treated eyes showed that functional photoreceptors were still present at 9 weeks, when there is virtually no activity in untreated control eyes. Histological analysis of treated eyes revealed a decrease in the amount of debris in the subretinal space, suggesting that RPE function was restored. Moreover, 9 weeks after treatment the number of photoreceptors was 2.5-fold higher in treated than in control eyes. This study provides strong support for the development of AAV-mediated gene therapy for RP caused by mutations in the MERTK gene.
Mol Ther 2003 Aug
PMID:AAV-Mediated gene transfer slows photoreceptor loss in the RCS rat model of retinitis pigmentosa. 1290 41

Mutations within the CRB1 gene have been shown to cause human retinal diseases including retinitis pigmentosa and Leber congenital amaurosis. We have recently identified a mouse model, retinal degeneration 8 (rd8) with a single base deletion in the Crb1 gene. This mutation is predicted to cause a frame shift and premature stop codon which truncates the transmembrane and cytoplasmic domain of CRB1. Like in Drosophila crumbs (crb) mutants, staining for adherens junction proteins known to localize to the external limiting membrane, the equivalent of the zonula adherens in the mammalian retina, is discontinuous and fragmented. Shortened photoreceptor inner and outer segments are observed as early as 2 weeks after birth, suggesting a developmental defect in these structures rather than a degenerative process. Photoreceptor degeneration is observed only within regions of retinal spotting, which is seen predominantly in the inferior nasal quadrant of the eye, and is caused by retinal folds and pseudorosettes. Photoreceptor dysplasia and degeneration in Crb1 mutants strongly vary with genetic background, suggesting that the variability in phenotypes of human patients that carry mutations in CRB1 may be due to interactions with background modifiers in addition to allelic variations. The Crb1rd8 mouse model will facilitate the analysis of Crb1 function in the neural retina and the identification of interacting factors as candidate retinal disease genes.
Hum Mol Genet 2003 Sep 01
PMID:CRB1 is essential for external limiting membrane integrity and photoreceptor morphogenesis in the mammalian retina. 1291 75

Peripherin-2 is a member of the tetraspanin family of membrane proteins that plays a critical role in photoreceptor outer segment disk morphogenesis. Mutations in peripherin-2 are responsible for various retinal degenerative diseases including autosomal dominant retinitis pigmentosa (ADRP). To identify determinants required for peripherin-2 targeting to disk membranes and elucidate mechanisms underlying ADRP, we have generated transgenic Xenopus tadpoles expressing wild-type and ADRP-linked peripherin-2 mutants as green fluorescent fusion proteins in rod photoreceptors. Wild-type peripherin-2 and P216L and C150S mutants, which assemble as tetramers, targeted to disk membranes as visualized by confocal and electron microscopy. In contrast the C214S and L185P mutants, which form homodimers, but not tetramers, were retained in the rod inner segment. Only the P216L disease mutant induced photoreceptor degeneration. These results indicate that tetramerization is required for peripherin-2 targeting and incorporation into disk membranes. Tetramerization-defective mutants cause ADRP through a deficiency in wild-type peripherin-2, whereas tetramerization-competent P216L peripherin-2 causes ADRP through a dominant negative effect, possibly arising from the introduction of a new oligosaccharide chain that destabilizes disks. Our results further indicate that a checkpoint between the photoreceptor inner and outer segments allows only correctly assembled peripherin-2 tetramers to be incorporated into nascent disk membranes.
Mol Biol Cell 2003 Aug
PMID:The role of subunit assembly in peripherin-2 targeting to rod photoreceptor disk membranes and retinitis pigmentosa. 1292 72

Recessive splice site and nonsense mutations of PCDH15, encoding protocadherin 15, are known to cause deafness and retinitis pigmentosa in Usher syndrome type 1F (USH1F). Here we report that non-syndromic recessive hearing loss (DFNB23) is caused by missense mutations of PCDH15. This suggests a genotype-phenotype correlation in which hypomorphic alleles cause non-syndromic hearing loss, while more severe mutations of this gene result in USH1F. We localized protocadherin 15 to inner ear hair cell stereocilia, and to retinal photoreceptors by immunocytochemistry. Our results further strengthen the importance of protocadherin 15 in the morphogenesis and cohesion of stereocilia bundles and retinal photoreceptor cell maintenance or function.
Hum Mol Genet 2003 Dec 15
PMID:PCDH15 is expressed in the neurosensory epithelium of the eye and ear and mutant alleles are responsible for both USH1F and DFNB23. 1457 Jul 5

Mutations in the rhodopsin gene are the most common cause of retinitis pigmentosa (RP) among human patients. The nature of the rhodopsin mutations has critical implications for the design of strategies for gene therapy. Nearly all rhodopsin mutations are dominant. Although dominance does not arise because of haploinsufficiency, it is unclear whether it is caused by gain-of-function or dominant-negative mutations. Current strategies for gene therapy have been devised to deal with toxic, gain-of-function mutations. However, analysis of results of transgenic and targeted expression of various rhodopsin genes in mice suggests that dominance may arise as a result of dominant-negative mutations. This has important consequences for gene therapy. The effects of dominant-negative mutations can be alleviated, in principle, by supplementation with additional wild-type rhodopsin. If added wild-type rhodopsin could slow retinal degeneration in human patients, as it does in mice, it would represent a valuable new strategy for gene therapy of RP caused by dominant rhodopsin mutations.
Mol Neurobiol 2003 Oct
PMID:The nature of dominant mutations of rhodopsin and implications for gene therapy. 1457 53

Crumbs is an apical transmembrane protein crucial for epithelial morphogenesis in Drosophila melanogaster embryos. A protein with all the characteristics for a Crumbs homologue has been identified from patients suffering from retinitis pigmentosa group 12, but this protein (CRB1) is only expressed in retina and some parts of the brain, both in human and mouse. Here, we describe CRB3, another Crumbs homologue that is preferentially expressed in epithelial tissues and skeletal muscles in human. CRB3 shares the conserved cytoplasmic domain with other Crumbs but exhibits a very short extracellular domain without the EGF- and laminin A-like G repeats present in the other Crumbs. CRB3 is localized to the apical and subapical area of epithelial cells from the mouse and human intestine, suggesting that it could play a role in epithelial morphogenesis. Indeed, expression of CRB3 or of a chimera containing the extracellular domain of the neurotrophin receptor p75NTR and the transmembrane and cytoplasmic domains of CRB3 led to a slower development of functional tight junctions in Madin-Darby canine kidney cells. This phenotype relied on the presence of CRB3 four last amino acids (ERLI) that are involved in a direct interaction with Par6, a regulator of epithelial polarity and tight junction formation. Thus, CRB3, through its cytoplasmic domain and its interactors, plays a role in apical membrane morphogenesis and tight junction regulation.
Mol Biol Cell 2004 Mar
PMID:CRB3 binds directly to Par6 and regulates the morphogenesis of the tight junctions in mammalian epithelial cells. 2293 96


<< Previous 1 2 3 4 5 6 7 8 9 10