Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0025362 (mental retardation)
 15,878 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Vertebrate studies show neuroligins and neurexins are binding partners in a trans-synaptic cell adhesion complex, implicated in human autism and mental retardation disorders. Here we report a genetic analysis of homologous proteins in the honey bee. As in humans, the honeybee has five large (31-246 kb, up to 12 exons each) neuroligin genes, three of which are tightly clustered. RNA analysis of the neuroligin-3 gene reveals five alternatively spliced transcripts, generated through alternative use of exons encoding the cholinesterase-like domain. Whereas vertebrates have three neurexins the bee has just one gene named neurexin I (400 kb, 28 exons). However alternative isoforms of bee neurexin I are generated by differential use of 12 splice sites, mostly located in regions encoding LNS subdomains. Some of the splice variants of bee neurexin I resemble the vertebrate alpha- and beta-neurexins, albeit in vertebrates these forms are generated by alternative promoters. Novel splicing variations in the 3' region generate transcripts encoding alternative trans-membrane and PDZ domains. Another 3' splicing variation predicts soluble neurexin I isoforms. Neurexin I and neuroligin expression was found in brain tissue, with expression present throughout development, and in most cases significantly up-regulated in adults. Transcripts of neurexin I and one neuroligin tested were abundant in mushroom bodies, a higher order processing centre in the bee brain. We show neuroligins and neurexins comprise a highly conserved molecular system with likely similar functional roles in insects as vertebrates, and with scope in the honeybee to generate substantial functional diversity through alternative splicing. Our study provides important prerequisite data for using the bee as a model for vertebrate synaptic development.
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PMID:Bridging the synaptic gap: neuroligins and neurexin I in Apis mellifera. 1897 85

Recent studies have supported the hypothesis based upon expectations from population genetics that the high heritability of schizophrenia reflects a combination of relatively common alleles of small effect and rare alleles some with relatively large effects. Genome-wide association studies have identified a number of risk loci at genome-wide levels of significance as well as evidence for a substantial burden of common risk loci. Moreover these recent findings suggest genetic overlap with bipolar disorder which has traditionally been assumed to be genetically distinct from schizophrenia. Genome-wide studies of at least one class of relatively uncommon variant, submicroscopic chromosomal abnormalities often referred to as copy number variations (CNVs), suggest that these confer high risk of schizophrenia. There is evidence both for an increased burden of large, rare CNVs in schizophrenia and that risk is conferred by a number of specific large CNVs as well as by deletions of NRXN1 which encodes the synaptic scaffolding protein neurexin 1. Many of these CNVs have been implicated in autism, mental retardation, epilepsy and other neurodevelopment disorders. These findings have implications for pathogenesis and nosology of schizophrenia and related disorders, and for future genetic studies.
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PMID:Recent genomic advances in schizophrenia. 2189 34