The Dispanins: A Novel Gene Family of Ancient Origin That Contains 14 Human Members

The Interferon induced transmembrane proteins (IFITM) are a family of transmembrane proteins that is known to inhibit cell invasion of viruses such as HIV-1 and influenza. We show that the IFITM genes are a subfamily in a larger family of transmembrane (TM) proteins that we call Dispanins, which refers to a common 2TM structure. We mined the Dispanins in 36 eukaryotic species, covering all major eukaryotic groups, and investigated their evolutionary history using Bayesian and maximum likelihood approaches to infer a phylogenetic tree. We identified ten human genes that together with the known IFITM genes form the Dispanin family. We show that the Dispanins first emerged in eukaryotes in a common ancestor of choanoflagellates and metazoa, and that the family later expanded in vertebrates where it forms four subfamilies (A–D). Interestingly, we also find that the family is found in several different phyla of bacteria and propose that it was horizontally transferred to eukaryotes from bacteria in the common ancestor of choanoflagellates and metazoa. The bacterial and eukaryotic sequences have a considerably conserved protein structure. In conclusion, we introduce a novel family, the Dispanins, together with a nomenclature based on the evolutionary origin

The quantification of COMT mRNA in post mortem cerebellum tissue: diagnosis, genotype, methylation and expression

BACKGROUND: The COMT gene is located on chromosome 22q11, a region strongly implicated in the aetiology of several psychiatric disorders, in particular schizophrenia. Previous research has suggested that activity and expression of COMT is altered in schizophrenia, and is mediated by one or more polymorphisms within the gene, including the functional Val(158)Met polymorphism. METHOD: In this study we examined the expression levels of COMT mRNA using quantitative RT-PCR in 60 post mortem cerebellum samples derived from individuals with schizophrenia, bipolar disorder, depression, and no history of psychopathology. Furthermore, we have examined the methylation status of two CpG sites in the promoter region of the gene. RESULTS: We found no evidence of altered COMT expression or methylation in any of the psychiatric diagnoses examined. We did, however, find evidence to suggest that genotype is related to COMT gene expression, replicating the findings of two previous studies. Specifically, val(158)met (rs165688; Val allele) rs737865 (G allele) and rs165599 (G allele) all showed reduced expression (P < 0.05). Finally, we observe a strong sexual dimorphism in COMT expression, with females exhibiting significantly greater levels of COMT mRNA. CONCLUSION: The expression of COMT does not appear to be altered in the cerebellum of individuals suffering from schizophrenia, bipolar disorder or depression, but does appear to be influenced by single nucleotide polymorphisms within the gene

Global Expression Profiling in Epileptogenesis: Does It Add to the Confusion?

Since the inception of global gene expression profiling platforms in the mid-1990s, there has been a significant increase in publications of differentially expressed genes in the process of epileptogenesis. In particular for mesial temporal lobe epilepsy, the presence of a latency period between the first manifestation of seizures to chronic epilepsy provides the opportunity for therapeutic interventions at the molecular biology level. Using global expression profiling techniques, approximately 2000 genes have been published demonstrating differential expression in mesial temporal epilepsy. The majority of these changes, however, are specific to laboratory or experimental conditions with only 53 genes demonstrating changes in more than two publications. To this end, we review the current status of gene expression profiling in epileptogenesis and suggest standard guidelines to be followed for greater accuracy and reproducibility of results

Genome-Wide Association Study of Treatment Refractory Schizophrenia in Han Chinese

We report the first genome-wide association study of a joint analysis using 795 Han Chinese individuals with treatment-refractory schizophrenia (TRS) and 806 controls. Three loci showed suggestive significant association with TRS were identified. These loci include: rs10218843 (P = 3.04×10−7) and rs11265461 (P = 1.94×10−7) are adjacent to signaling lymphocytic activation molecule family member 1 (SLAMF1); rs4699030 (P = 1.94×10−6) and rs230529 (P = 1.74×10−7) are located in the gene nuclear factor of kappa light polypeptide gene enhancer in B-cells 1 (NFKB1); and rs13049286 (P = 3.05×10−5) and rs3827219 (P = 1.66×10−5) fall in receptor-interacting serine/threonine-protein kinase 4 (RIPK4). One isolated single nucleotide polymorphism (SNP), rs739617 (P = 3.87×10−5) was also identified to be associated with TRS. The -94delATTG allele (rs28362691) located in the promoter region of NFKB1 was identified by resequencing and was found to associate with TRS (P = 4.85×10−6). The promoter assay demonstrated that the -94delATTG allele had a significant lower promoter activity than the -94insATTG allele in the SH-SY5Y cells. This study suggests that rs28362691 in NFKB1 might be involved in the development of TRS

Functional heterogeneity of gephyrins

Postsynaptic clustering of the glycine receptor requires the cytoplasmic protein gephyrin, which interacts with the receptor beta subunit. Several variants of gephyrin are generated by alternative splicing and differ by the presence of short amino acid sequences (cassettes) in the N-terminal half of the molecule. In this work, seven isoforms of gephyrin were cloned from adult rat spinal cord, some of then containing new cassettes. The relationships between gephyrin structure and recognition of glycine receptor beta subunit were analyzed. This was carried out by GST-pulldown assays using the beta subunit cytoplasmic loop and cotransfection experiments of GFP-tagged gephyrins with an alpha1 subunit bearing the gephyrin-binding site of the beta subunit. Data demonstrated that not all gephyrin molecules can bind to the beta subunit. Identified cassettes modulate this interaction. It is thus concluded that the function of gephyrin in synapse formation can rely on a structure acquired through cassette combinations

Doublecortin-like kinase 3 (DCLK3), a novel striatum-enriched species, is amodulator of mutant huntingtin in vivo

International audienceHuntington's disease (HD) is a neurodegenerative disorder caused by an abnormal CAG repeat expansion coding for an expanded polyglutamine tract in the protein "huntingtin" (Htt). Although this mutant Htt (mHtt) is expressed ubiquitously throughout the brain, the striatum is found preferentially affected. One hypothesis to explain this particular vulnerability is that striatal neurons express a particular set of proteins that make them highly vulnerable to mHtt. In order to further examine this hypothesis, we carried out a transcriptome analysis of different brain territories and identified more than 100 molecular markers i.e. transcripts that are highly enriched in the mouse striatum. We recently focused our interest on a subset of striatal-enriched transcripts of poorly characterized transcripts. We here report the study of one of these markers, the CAMKII family-related kinase DCLK3. We found that DCLK3 is mainly expressed in the adult striatum in rodent with low level of expression in the newborn and striatal primary cultures. Reduced mRNA levels of DCLK3 were found in the striatum of transgenic mouse models of HD. We thus studied the effect of DCLK3 overexpression and knock-down in a mouse model of HD using lentiviral vectors coding for a N-terminal fragment of mHtt. DCLK3 and its related siRNA were delivered using lentiviral vectors. Striatal degeneration produced by mHtt was characterized using immunohistochemistry of DARPP32, Cytochrome oxidase and ubiquitin followed by quantitative histological evaluation. Results showed that lenti-siRNA targeting DCLK3 increased mHtt toxicity when compared to the control. On the contrary, overexpression of DCLK3 reduced the striatal lesions produced by mHtt in vivo. DCLK3 also decreased the number and size of ubiquitin-containing nuclear inclusions. Current experiments are examining the mechanisms that could underlie the neuroprotective effect of DCLK3 in striatal neurons. The present study 4/6/202

2010001M06rik (St102) protects striatal neurons against an N-terminal fragmentof mutant huntingtin in vivo

International audienceThe mechanisms underlying the preferential vulnerability of striatal neurons to mutant Huntingtin (mHtt) in Huntington's disease (HD) remain unknown. Our hypothesis, supported by recent publications, is that genes selectively expressed in the striatum may play a role in this susceptibility to mHtt. In the present study we focused on a product of the 2010001M06rik (St102) gene, previously identified based on its preferential expression in the striatum and its significantly reduced levels in the striatum of R6/2 mice (Brochier et al., Physiol Genomics, 2008). We examined whether modifying St102 expression could change the neurotoxic effects of an N-terminal fragment of mHtt expressed in the mouse striatum using the HD lentiviral model (LV-Htt171-82Q). We developed lentiviral vectors to overexpress St102 (LV-St102) or knock-down St102 using a selective shRNA (LV-shRNA-St102). RT-PCR analysis infection of the striatum of adult mice with LV-St102 or LV-shRNA-St102 led to a significant increase or decrease of St102 expression respectively, without producing overt alterations as assessed using immunohistochemistry (IHC) of NeuN and DARPP32. LV-St102 and LV-shRNA-St102 were co-injected with LV-Htt171-82Q in the striatum of adult WT mice. Six weeks after injections, LV-Htt171-82Q consistently produced striatal lesions characterized by a loss of NeuN and DARPP32. Interestingly, the co-expression of Htt171-82Q and shRNA-St102 led to a significant increase in the lesion volume. On the contrary, the co-expression of Htt171-82Q and St102 overexpression led to a significant decrease of the lesion size. These results suggest that the loss of St102 expression could play a role in striatal degeneration in HD