UNIPROT:Q00604 - FACTA Search

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Query: UNIPROT:Q00604 (X-linked)
16,883 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We investigated the expression of two different X-linked Kallmann (KAL) gene cDNAs in two different cell-free systems using rabbit reticulocyte lysate: (system A) transcription/translation coupled and (system B) noncoupled. System A yielded a single band of 76 kDa corresponding to anosmin-1, the expected full-length gene product, and upon addition of canine microsomal membranes produced a 85-kDa glycosylated form. System B did not produce any detectable protein band despite the expression of a beta-galactosidase-positive control gene. The first 179 bases of the coding sequence are 74% GC-rich and showed the potential to form imperfect hairpin structures, which in part may explain the translation inhibition of KAL in system B. This has further led us to speculate that coupling transcription to translation may either be preventing translating-inhibiting hairpin formation or be compensating for the lack of certain tissue-specific proteins in reticulocyte lysate that are essential in overcoming inhibitory hairpins during translation. Substitution of the 5'-UTR with an encephalomyocarditis virus internal ribosomal entry site (EMCV IRES) sequence resulted paradoxically in a lower yield of anosmin-1, suggesting that elements in the 5'UTR may be necessary for maintaining a "normal" level of expression. The use of KAL and luciferase reporters (containing different 5'UTRs) demonstrated that the native KAL 5' UTR is not involved in translational efficiency. However, this sequence may influence faithful translation initiation. Theoretical RNA conformation data imply that effective EMCV IRES usage with KAL may require favorable pairing between the IRES and unidentified sequences within the 5' coding region of the gene. This work provides a foundation both for the investigation of KAL regulation and for the characterization of its function.
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PMID:Contrasting expression of KAL in cell-free systems: 5' UTR and coding region structural effects on translation. 967 68

Anosmin-1 is an extracellular matrix glycoprotein which underlies the X chromosome-linked form of Kallmann syndrome. This disease is characterized by hypogonadism due to GnRH deficiency, and a defective sense of smell related to the underdevelopment of the olfactory bulbs. This study reports that anosmin-1 is an adhesion molecule for a variety of neuronal and non-neuronal cell types in vitro. We show that cell adhesion to anosmin-1 is dependent on the presence of heparan sulfate and chondroitin sulfate glycosaminoglycans at the cell surface. A major cell adhesion site of anosmin-1 was identified in a 32 amino acid (32R1) sequence located within the first fibronectin-like type III repeat of the protein. The role of anosmin-1 as a substrate for neurite growth was tested on either coated culture dishes or monolayers of anosmin-1-producing CHO cells. In both experimental systems, anosmin-1 was shown to be a permissive substrate for the neurite growth of different types of neurons. Mouse P5 cerebellar neurons cultured on anosmin-1 coated wells developed long neurites; the 32R1 peptide was found to underly part of this neurite growth activity. When the cerebellar neurons were cultured on anosmin-1-producing CHO cells, neurite growth was reduced as compared to wild-type CHO cells; in contrast, no difference was observed for E18 hippocampal and P1 dorsal root ganglion neurons in the same experimental system. These results indicate that anosmin-1 can modulate neurite growth in a cell-type specific manner. Finally, anosmin-1 induced neurite fasciculation of P5 cerebellar neuron aggregates cultured on anosmin-1-producing CHO cells. The pathogenesis of the olfactory defect in the X-linked Kallmann syndrome is discussed in the light of the present results and the recent data reporting the immunohistochemical localisation of anosmin-1 during early embryonic development.
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PMID:Anosmin-1 underlying the X chromosome-linked Kallmann syndrome is an adhesion molecule that can modulate neurite growth in a cell-type specific manner. 973 Sep 87

Kallmann syndrome is a developmental disease characterized by gonadotropin-releasing hormone (GnRH) deficiency and olfactory bulb hypoplasia. The gene underlying the X chromosome-linked form, KAL-1, has been identified for several years, yet the pathogenesis of the disease is not understood. By immunohistofluorescence and immunoelectron microscopy, we establish that the KAL-1 encoded protein, anosmin-1, is a transient and regionally restricted component of extracellular matrices during organogenesis in man. Anosmin-1 was detected in the basement membranes and/or interstitial matrices of various structures including bronchial tubes, mesonephric tubules and duct, branches of the ureteric bud, muscular walls of the digestive tract and larger blood vessels, precartilaginous models of skeletal pieces, muscle tendons, head mesenchymes, inner ear, and forebrain subregions. Our results suggest that this protein acts as a local, rather than a long-range, cue during organogenesis. In the olfactory system, anosmin-1 was detected from week 5 onward. The protein was restricted to the olfactory bulb presumptive region and later, to the primitive olfactory bulbs. We therefore suggest that the genetic defect underlying X-linked Kallmann syndrome disrupts the terminal navigation of the early olfactory axons or directly affects the initial steps of olfactory bulb differentiation. The mechanism of the GnRH deficiency is also discussed, relying on the evidence that anosmin-1 is present in the medial walls of the primitive cerebral hemispheres, along the rostro-caudal migratory pathway of the GnRH-synthesizing neurons, at 6 weeks. Finally, the present results strongly suggest that the renal aplasia observed in about one third of the affected individuals results from primary failure of the collecting duct system.
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PMID:Anosmin-1 is a regionally restricted component of basement membranes and interstitial matrices during organogenesis: implications for the developmental anomalies of X chromosome-linked Kallmann syndrome. 1034 Jul 54

Some forms of isolated hypogonadotropic hypogonadism are caused by mutations of the GnRH receptor gene. These mutations lead to inactivation of the receptor and are recessive. A unique disease that associates hypogonadotropic hypogonadism and congenital hyperplasia is caused by mutations in the DAX-1 gene, situated on chromosome X. The pathogenesis to these endocrine defects remains now elusive. Kallmann syndrome represents the association of hypogonadotropic hypogonadism due to GnRH deficiency, and anosmia. Additional developmental anomalies can be present. Three modes of inheritance have been described: X-linked, autosomal recessive and autosomal dominant. The X-linked KAL-1 gene has been cloned. It encodes an extracellular matrix protein, anosmin-1, the study of which should lead to a better understanding of this developmental disease.
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PMID:[Genetic anomalies of the gonadotropic axis]. 1048 58

Kallmann syndrome (KS), defined by the association of hypogonadotropic hypogonadism and anosmia or hyposmia, can be caused by mutations in the KAL gene on Xp 22.3. This gene encodes an extracellular matrix glycoprotein called anosmin-1, which belongs to the class of cell adhesion molecules. In the absence of a functional KAL protein, migration of both olfactory and gonadotropin-releasing hormone neurons is arrested. A defective anosmin-1 molecule may also play a role in the development of synkinesia and renal agenesis, which are exclusively seen in the X-linked form of KS. We describe the clinical presentation and molecular diagnosis of the defect in two brothers with KS. An X-linked mode of transmission was assumed on the basis of synkinesia and the presence of oligomenorrhoea in the mother. A novel nonsense mutation was found in exon 13 of the KAL gene, encoding the region of the fourth fibronectin type III repeat of anosmin-1, which results in an apparently nonfunctional truncated protein.
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PMID:A novel nonsense mutation of the KAL gene in two brothers with Kallmann syndrome. 1104 5

Gonadotropin Releasing Hormone (GnRH) is a key regulator of reproduction and sexual behaviour. During the last decade, embryological studies have clarified the question of the early development of GnRH-synthesising neurones before the onset of neurosecretion. These studies have revealed the existence of a topographical link between GnRH-synthesising neurones and the embryonic olfactory system, thereby shedding new light on Kallmann syndrome, a developmental disease characterised by the association of hypogonadotropic hypogonadism and anosmia (or hyposmia). Although Kallmann syndrome was identified as an inherited disease in the forties, familial cases of the disease are infrequent. However, the identification, by positional cloning strategies, of the gene underlying the X-chromosome linked form of the disease (KAL-1) has opened the way to molecular pathophysiology. KAL-1 encodes an extracellular glycoprotein of compound modular structure. The protein, named anosmin-1, has been produced in a transfected mammalian cell line and purified. Polyclonal and monoclonal antibodies have been generated, which allowed us to study the distribution of the protein during the period of human organogenesis (4--10 embryonic weeks), by immunohistofluorescence. During this developmental period, anosmin-1 is a locally restricted component of various extracellular matrices (interstitial matrices and basement membranes). Later in embryonic life, KAL-1 expression apparently becomes restricted to definite neuronal populations. Based on the distribution of anosmin-1 in the early olfactory system, the pathogenesis of the olfactory loss and GnRH deficiency in X-linked Kallmann syndrome is discussed.
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PMID:Kallmann syndrome: towards molecular pathogenesis. 1142 Jan 33

Anosmin-1, the gene product of the KAL gene, is implicated in the pathogenesis of X-linked Kallmann's syndrome. Anosmin-1 protein expression is restricted to the basement membrane and interstitial matrix of tissues affected in this syndrome during development. The anosmin-1 sequence indicates an N-terminal cysteine-rich domain, a whey acidic protein (WAP) domain, four fibronectin type III (FnIII) domains and a C-terminal histidine-rich region, and shows similarity with cell-adhesion molecules, such as neural cell-adhesion molecule, TAG-1 and L1. We investigated the structural and functional significance of three loss-of-function missense mutations of anosmin-1 using comparative modelling of the four FnIII and the WAP domains based on known NMR and crystal structures. Three missense mutation-encoded amino acid substitutions, N267K, E514K and F517L, were mapped to structurally defined positions on the GFCC' beta-sheet face of the first and third FnIII domains. Electrostatic maps demonstrated large basic surfaces containing clusters of conserved predicted heparan sulphate-binding residues adjacent to these mutation sites. To examine these modelling results anosmin-1 was expressed in insect cells. The incorporation of the three mutations into recombinant anosmin-1 had no effect on its secretion. The removal of two dibasic motifs that may constitute potential physiological cleavage sites for anosmin-1 had no effect on cleavage. Peptides based on the anosmin-1 sequences R254--K285 and P504--K527 were then synthesized in order to assess the effect of the three mutations on cellular adhesion, using cell lines that represented potential functional targets of anosmin-1. Peptides (10 microg/ml) incorporating the N267K and E514K substitutions promoted enhanced adhesion to 13.S.1.24 rat olfactory epithelial cells and canine MDCK1 kidney epithelial cells (P<0.01) compared with the wild-type peptides. This result was attributed to the introduction of a lysine residue adjacent to the large basic surfaces. We predict that two of the three missense mutants increase the binding of anosmin-1 to an extracellular target, possibly by enhancing heparan sulphate binding, and that this critically affects the function of anosmin-1.
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PMID:Molecular modelling and experimental studies of mutation and cell-adhesion sites in the fibronectin type III and whey acidic protein domains of human anosmin-1. 1146 36

Kallmann syndrome is hypogonadotropic hypogonadism coupled with anosmia. A morphological study found that the endocrine disorder in X-linked Kallmann syndrome is due to failed migration of gonadotropin releasing-hormone (GnRH) neurons from the olfactory placode to the brain during development. Anosmia results from agenesis of the olfactory bulbs and tracts. The gene responsible for the X-linked form of Kallmann syndrome, KAL-1, has been characterized. The orthologues of KAL-1 have been isolated in the chick and the zebrafish, but still await identification in rodents. In the present study, we used polyclonal and monoclonal antibodies to the human KAL-1 encoded protein, anosmin-1, in a primitive mammal, the Asian musk shrew. Musk shrews are insectivores and are therefore evolutionarily closer to primates than rodents. By immunoblot analysis of musk shrew tissues, a band of the expected apparent molecular mass (95 kDa) was detected in several structures of the central nervous system, but not in liver or muscle, which is consistent with the gene expression pattern previously reported in the chick. By immunohistochemical analysis, anosmin-1 was detected in the developing olfactory epithelium, the olfactory, vomeronasal and terminalis nerves, the olfactory bulbs, the cerebellum and the cerebral cortex and in several other regions of the brain, during musk shrew embryogenesis. Furthermore, migrating gonadotropin releasing-hormone (GnRH)-immunoreactive neurons were seen in close association with anosmin-1-immunoreactive fibers. Assuming that the protein is present at the surface of these fibers, we suggest a possible direct role of anosmin-1 in the migration of GnRH neurons in this species.
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PMID:Anosmin-1 immunoreactivity during embryogenesis in a primitive eutherian mammal. 1258 22

Kallmann syndrome (KS) is characterized by the association of hypogonadotropic hypogonadism and anosmia. The gene underlying the X chromosome-linked form of the disease, KAL-1, consists of 14 coding exons. It encodes a glycoprotein, anosmin-1, which is involved in the embryonic migration of GnRH-synthesizing neurons and the differentiation of the olfactory bulbs. We describe herein the clinical heterogeneity in three affected brothers who carry a large deletion (exons 3-13) in KAL-1. All three had a history of hypogonadotropic hypogonadism with delayed puberty. Although brain magnetic resonance imaging showed hypoplastic olfactory bulbs in the three siblings, variable degrees of anosmia/hyposmia were shown by olfactometry. In addition, these brothers had different phenotypic anomalies, i.e. unilateral renal aplasia (siblings B and C), high-arched palate (sibling A), brachymetacarpia (sibling A), mirror movements (siblings A and B), and abnormal eye movements (sibling C). Last but not least, sibling A suffered from a severe congenital hearing impairment, a feature that had been reported in KS but had not yet been ascribed unambiguously to the X-linked form of the disease. The variable phenotype, both qualitatively and quantitatively, in this family further emphasizes the role of putative modifier genes, and/or epigenetic factors, in the expressivity of the X-linked KS.
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PMID:X chromosome-linked Kallmann syndrome: clinical heterogeneity in three siblings carrying an intragenic deletion of the KAL-1 gene. 1272 45

Kallmann's syndrome (KS) is a genetic condition characterised by hypogonadotrophic hypogonadism (HH) and anosmia; although these are the defining features of the condition, additional neurological and non-neurological sequel may also occur depending on the specific mode of inheritance. KS affects about 1 in 8000 males and 1 in 40,000 females, with most presentations being of the 'sporadic' type. Of the inherited forms, hitherto, only the gene responsible for the X-linked form (X-KS), namely KAL-1, has been identified and the encoded protein, anosmin-1, consists primarily of a whey acidic protein (WAP) and fibronectin-like type III (FnIII) domains which appear to mediate distinctly different protein functions. The WAP/FnIII combination is conserved in anosmins across species and recent studies in rodents and in Caenorhabditis elegans demonstrate that anosmin functions in both axonal targeting and branching. Screening for loci that modify these phenotypes in C. elegans has identified heparan-6-O-sulphotransferase as a key interactor mediating anosmin-1 function. Furthermore, over-expression and loss of function of the C. elegans Kal-1 gene disrupt epidermal morphogenesis, resulting in ventral enclosure and male tail formation defects. These findings provide novel insights into the molecular pathogenesis of X-KS.
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PMID:Kallmann's syndrome: molecular pathogenesis. 1275 52

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