Borderline and schizotypal traits in college students: Relationship and personality profiles

The relationships between borderline and schizotypal traits are still debated. Borderline traits, schizotypal traits, and several psychopathological symptoms were assessed among 2,341 college students. A factor analysis was performed on borderline and schizotypal personality measures, leading to 10 factors. Borderline factors were largely intercorrelated, as were schizotypal factors. Moreover, borderline factors were weakly to largely correlated to schizotypal factors. Five factors were very strongly correlated (r > .50). Dissociation was strongly related to Odd Beliefs/Unusual Perceptive Experiences and Anxious-Depressive factors. Social Anxiety was strongly related to Suspiciousness. Based on these 10 factors, a cluster analysis was conducted, and resulted in four clearly distinct groups: a Low Traits cluster, a Narcissistic cluster, a Social Anxiety cluster, and a High Traits cluster. This High Traits cluster had the lowest levels of academic achievement and the highest levels of internalizing behaviors and externalizing behaviors. The clinical implications of the results are discussed

Live imaging of targeted cell ablation in Xenopus:a new model to study demyelination and repair

Live imaging studies of the processes of demyelination and remyelination have so far been technically limited in mammals. We have thus generated a Xenopus laevis transgenic line allowing live imaging and conditional ablation of myelinating oligodendrocytes throughout the central nervous system (CNS). In these transgenic pMBP-eGFP-NTR tadpoles the myelin basic protein (MBP) regulatory sequences, specific to mature oligodendrocytes, are used to drive expression of an eGFP (enhanced green fluorescent protein) reporter fused to the E. coli nitroreductase (NTR) selection enzyme. This enzyme converts the innocuous pro-drug metronidazole (MTZ) to a cytotoxin. Using two-photon imaging in vivo, we show that pMBP-eGFP-NTR tadpoles display a graded oligodendrocyte ablation in response to MTZ, which depends on the exposure time to MTZ. MTZ-induced cell death was restricted to oligodendrocytes, without detectable axonal damage. After cessation of MTZ treatment, remyelination proceeded spontaneously, but was strongly accelerated by retinoic acid. Altogether, these features establish the Xenopus pMBP-eGFP-NTR line as a novel in vivo model for the study of demyelination/remyelination processes and for large-scale screens of therapeutic agents promoting myelin repair

L’effet modérateur de la pleine conscience dispositionnelle dans la relation entre symptomatologie dépressive, troubles de la personnalité limite et idéations suicidaires chez le jeune adulte

International audienceL'effet modérateur de la pleine conscience dispositionnelle dans la relation entre symptomatologie dépressive, troubles de la personnalité limite et idéations suicidaires chez le jeune adulte

A gene trap approach in Xenopus

AbstractThe frog transgenesis technique ultimately promises to make mutagenesis possible through random insertion of plasmid DNA into the genome. This study was undertaken to evaluate whether a gene trap approach combined with transgenesis would be appropriate for performing insertional mutagenesis in Xenopus embryos. Firstly, we confirmed that the transgenic technique results in stable integration into the genome and that transmission through the germline occurs in the expected Mendelian fashion. Secondly, we developed several gene trap vectors, using the green fluorescent protein (GFP) as a marker. Using these vectors, we trapped several genes in Xenopus laevis that are expressed in a spatially restricted manner, including expression in the epiphysis, the olfactory bulb and placodes, the eyes, ear, brain, muscles, tail and intestine. Finally, we cloned one of the trapped genes using 5′ rapid amplification of cDNA ends polymerase chain reaction (RACE PCR). These results suggest that the transgenic technique combined with a gene trap approach might provide a powerful method for generating mutations in endogenous genes in Xenopus

Characterization of a Xenopus tropicalis Endogenous Retrovirus with Developmental and Stress-Dependent Expression ▿ †

We report on the identification and characterization of XTERV1, a full-length endogenous retrovirus (ERV) within the genome of the western clawed frog (Xenopus tropicalis). XTERV1 contains all the basic genetic elements common to ERVs, including the classical 5′-long terminal repeat (LTR)-gag-pol-env-3′-LTR architecture, as well as conserved functional motifs inherent to each retroviral protein. Using phylogenetic analysis, we show that XTERV1 is related to the Epsilonretrovirus genus. The X. tropicalis genome harbors a single full-length copy with intact gag and pol open reading frames that localizes to the centromeric region of chromosome 5. About 10 full-length defective copies of XTERV1 are found interspersed in the genome, and 2 of them could be assigned to chromosomes 1 and 3. We find that XTERV1 genes are zygotically transcribed in a regulated spatiotemporal manner during frog development, including metamorphosis. Moreover, XTERV1 transcription is upregulated under certain cellular stress conditions, including cytotoxic and metabolic stresses. Interestingly, XTERV1 Env is found to be homologous to FR47, a protein upregulated following cold exposure in the freeze-tolerant wood frog (Rana sylvatica). In addition, we find that R. sylvatica FR47 mRNA originated from a retroviral element. We discuss the potential role(s) of ERVs in physiological processes in vertebrates

Comparison of Morpholino based translational inhibition during the development of Xenopus laevis and Xenopus tropicalis

International audienceMorpholino (MO) based inhibition of translational initiation represents an attractive methodology to eliminate gene function during Xenopus development (Heasman et al., 2000). However, the degree to which a given target protein can be eliminated and the longevity of this effect during embryogenesis has not been documented. To examine the efficacy of MOs, we have used transgenic Xenopus lines that harbour known numbers of integrations of a GFP reporter under the control of the ubiquitous and highly expressed CMV promoter (Fig. 1a). In addition we have investigated the longevity of the inhibitory effect by using transgenic lines expressing GFP specifically in the lens of tadpoles. These transgenic lines represent the ideal control for the technique as the promoters are highly expressed and GFP can be easily detected by fluorescence and immunoblotting. Moreover, as GFP has no function in development, the levels of inhibition can be tested in an otherwise normal individual. Here we report that MOs are able to efficiently and specifically inhibit the translation of GFP in transgenic lines from Xenopus laevis and Xenopus tropicalis and the inhibitory effect is long-lived, lasting into the tadpole stages. genesis 30:110--113, 2001

The olig family: phylogenetic analysis and early gene expression in Xenopus tropicalis.

International audienceThe olig genes form a small subfamily of basic helix-loop-helix transcription factors. They were discovered in 2000 as genes required for oligodendrocyte lineage specification. Since then, olig genes have been identified in various vertebrate species and corresponding sequences accumulated within genomic databases. Until now, three groups of olig genes have been characterized. Our phylogenetic analysis demonstrates the existence of a fourth group, which we named olig4. Genes of the four olig groups are present in actinopterygians and amphibians, whereas mammals only possess olig1, 2, and 3. We also found one olig gene in hemichordates, urochordates, and cephalochordates. Our expression study during Xenopus tropicalis embryogenesis shows that the four olig genes have very distinct expression patterns. Olig1 is very faintly expressed before the tadpole stage, whereas olig2, 3, and 4 are expressed from the gastrula stage onward. The olig3 expression during neurulation suggests a role in early anteroposterior patterning of the brain. All these results indicate that olig genes are involved in several developmental processes during early development

Phylogenomic analysis and expression patterns of large Maf genes in Xenopus tropicalis provide new insights into the functional evolution of the gene family in osteichthyans.

We have performed an exhaustive characterization of the large Maf family of basic leucine zipper transcription factors in vertebrates using the genome data available, and studied the embryonic expression patterns of the four paralogous genes thus identified in Xenopus tropicalis. Our phylogenetic analysis shows that, in osteichthyans, the large Maf family contains four orthology classes, MafA, MafB, c-Maf and Nrl, which have emerged in vertebrates prior to the split between actinopterygians and sarcopterygians. It leads to the unambiguous assignment of the Xenopus laevis XLmaf gene, previously considered a MafA orthologue, to the Nrl class, the identification of the amphibian MafA and c-Maf orthologues and the identification of the zebrafish Nrl gene. The four X. tropicalis paralogues display partially redundant but nevertheless distinct expression patterns in the somites, developing hindbrain, pronephros, ventral blood island and lens. Comparisons with the data available in the mouse, chick and zebrafish show that these large Maf expression territories are highly conserved among osteichthyans but also highlight a number of differences in the timing of large Maf gene expression, the precise extent of some labelled territories and the combinations of paralogues transcribed in some organs. In particular, the availability of robust phylogenies leads to a reinterpretation of previous expression pattern comparisons, suggesting an important part for function shuffling within the gene family in the developing lens. These data highlight the importance of exhaustive characterizations of gene families for comparative analyses of the genetic mechanisms, which control developmental processes in vertebrates

Characterization of a novel Xenopus tropicalis cell line as a model for in vitro studies

Chantier qualité GACell lines are useful tools to facilitate in vitro studies of many biological and molecular processes. We describe a new permanent fibroblast-type cell line obtained from disaggregated Xenopus tropicalis limb bud. The cell line population doubling time was _ 24 h. Its karyotype was genetically stable with a chromosome number of 2n 5 21 and a chromosome 10 trisomy. These cells could be readily transfected and expressed transgenes faithfully. We obtained stable transformants using transposon-based gene transfer technology. These cells responded to thyroid hormone and thus can provide a complementary research tool to study thyroid hormone signaling events. In conclusion, this cell line baptized ‘‘Speedy’’ should prove useful to couple in vitro and in vivo biological studies in the X. tropicalis frog model