A Genome-Wide Collection of Mos1 Transposon Insertion Mutants for the C. elegans Research Community

Methods that use homologous recombination to engineer the genome of C. elegans commonly use strains carrying specific insertions of the heterologous transposon Mos1. A large collection of known Mos1 insertion alleles would therefore be of general interest to the C. elegans research community. We describe here the optimization of a semi-automated methodology for the construction of a substantial collection of Mos1 insertion mutant strains. At peak production, more than 5,000 strains were generated per month. These strains were then subject to molecular analysis, and more than 13,300 Mos1 insertions characterized. In addition to targeting directly more than 4,700 genes, these alleles represent the potential starting point for the engineered deletion of essentially all C. elegans genes and the modification of more than 40% of them. This collection of mutants, generated under the auspices of the European NEMAGENETAG consortium, is publicly available and represents an important research resource

Dose-effect study of Gelsemium sempervirens in high dilutions on anxiety-related responses in mice

Introduction This study was designed to investigate the putative anxiolytic-like activity of ultra-low doses of Gelsemium sempervirens (G. sempervirens), produced according to the homeopathic pharmacopeia. Methods Five different centesimal (C) dilutions of G. sempervirens (4C, 5C, 7C, 9C and 30C), the drug buspirone (5 mg/kg) and solvent vehicle were delivered intraperitoneally to groups of ICR-CD1 mice over a period of 9 days. The behavioral effects were assessed in the open-field (OF) and light\u2013dark (LD) tests in blind and randomized fashion. Results Most G. sempervirens dilutions did not affect the total distance traveled in the OF (only the 5C had an almost significant stimulatory effect on this parameter), indicating that the medicine caused no sedation effects or unspecific changes in locomotor activity. In the same test, buspirone induced a slight but statistically significant decrease in locomotion. G. sempervirens showed little stimulatory activity on the time spent and distance traveled in the central zone of the OF, but this effect was not statistically significant. In the LD test, G. sempervirens increased the % time spent in the light compartment, an indicator of anxiolytic-like activity, with a statistically significant effect using the 5C, 9C and 30C dilutions. These effects were comparable to those of buspirone. The number of transitions between the compartments of the LD test markedly increased with G. sempervirens 5C, 9C and 30C dilutions. Conclusion The overall pattern of results provides evidence that G. sempervirens acts on the emotional reactivity of mice, and that its anxiolytic-like effects are apparent, with a non-linear relationship, even at high dilutions

Two unrelated patients with inversions of the X chromosome and non-specific mental retardation: physical and transcriptional mapping of their common breakpoint region in Xq13.1

Two unrelated mildly retarded males with inversions of the X chromosome and non-specific mental retardation (MRX) are described. Case 1 has a pericentric inversion 46,Y,inv(X)(p11.1q13.1) and case 2 a paracentric inversion 46,Y,inv(X) (q13.1q28). Both male patients have severe learning difficulties. The same chromosomal abnormalities were found in their mothers who are intellectually normal. Fluorescence in situ hybridisation mapping showed a common area of breakage of each of the inverted chromosomes in Xq13.1 near DXS131 and DXS162. A detailed long range restriction map of the breakpoint region was constructed using YAC, PAC, and cosmid clones. We show that the two inverted chromosomes break within a short 250 kb region. Moreover, a group of ESTs corresponding to an as yet uncharacterised gene was mapped to the same critical interval. We hypothesise that the common inversion breakpoint region of the two cases in Xq13.1 may contain a new MRX gene.


Keywords: inverted X chromosome; non-specific X linked mental retardation; XLMR; MR

Sequence family variant loss from the AZFc interval of the human Y chromosome, but not gene copy loss, is strongly associated with male infertility

Background: Complete deletion of the complete AZFc interval of the Y chromosome is the most common known genetic cause of human male infertility. Two partial AZFc deletions (gr/gr and b1/b3) that remove some copies of all AZFc genes have recently been identified in infertile and fertile populations, and an association study indicates that the resulting gene dose reduction represents a risk factor for spermatogenic failure. Methods: To determine the incidence of various partial AZFc deletions and their effect on fertility, we combined quantitative and qualitative analyses of the AZFc interval at the DAZ and CDY1 loci in 300 infertile men and 399 control men. Results: We detected 34 partial AZFc deletions (32 gr/gr deletions), arising from at least 19 independent deletion events, and found gr/gr deletion in 6% of infertile and 3.5% of control men (p>0.05). Our data provide evidence for two large AZFc inversion polymorphisms, and for relative hot and cold spots of unequal crossing over within the blocks of homology that mediate gr/gr deletion. Using SFVs (sequence family variants), we discriminate DAZ1/2, DAZ3/4, CDY1a (proximal), and CDY1b (distal) and define four types of DAZ-CDY1 gr/gr deletion. Conclusions: The only deletion type to show an association with infertility was DAZ3/4-CDY1a (p = 0.042), suggesting that most gr/gr deletions are neutral variants. We see a stronger association, however, between loss of the CDY1a SFV and infertility (p = 0.002). Thus, loss of this SFV through deletion or gene conversion could be a major risk factor for male infertility

Finding <i>Mos1</i> alleles with MosLocator.

<p>(A) MosLocator (<a href="http://www.ciml.univ-mrs.fr/applications/MosLocator" target="_blank">www.ciml.univ-mrs.fr/applications/MosLocator</a>) finds <i>Mos1</i> alleles using gene sequence or transcript names. For large lists of genetic gene names, the gene sequence or transcript names can be obtained using WormMart, or here, using WormBase Converter (<a href="http://www.ciml.univ-mrs.fr/applications/WB_converter" target="_blank">www.ciml.univ-mrs.fr/applications/WB_converter</a>) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0030482#pone.0030482-Engelmann1" target="_blank">[15]</a>. In the example shown, the 23 <i>ptr</i> genes were used as input. (B) Screen grabs were captured to illustrate the use of MosLocator. Left panel: a list of sequence names was entered, and the search parameters were defined. Upper right panel: a display of the output for this search. Clicking on a non-zero number displayed in either of the last two columns, for example the “2” associated with the gene T21H3.2 (<i>ptr-16</i>), generates the display shown in the inset. This is a list of the 2 <i>Mos1</i> mutant alleles that are found within the gene T21H3.2. Each allele name is hyperlinked to Wormbase. (C) A partial view of the Variation report for the <i>Mos1</i> allele <i>ttTi21065</i> found on chromosome V at Wormbase (version WS225). (D) The genomic environment of the <i>ttTi21065</i> allele is displayed. The figure is a screen-grab from Wormbase.</p

Summary of <i>Mos1</i> mutant production and characterization.

<p>Summary of <i>Mos1</i> mutant production and characterization.</p

Genome-wide distribution of <i>Mos1</i> mutant alleles.

<p>Chr: chromosome.</p

Genomic coverage of <i>Mos1</i>.

<p>Graphical representation of each <i>C. elegans</i> chromosome showing the regions of the genome that are potentially amenable to genome engineering using the publicly-available <i>Mos1</i> alleles; it is assumed that any point up to 1.5 kb away from a transposon-insertion site can be targeted. The bottom line is a magnified view of the boxed region on chromosome X.</p

Distribution of <i>Mos1</i> alleles.

<p>(A) Graph showing the relationship between chromosome length (as a percentage of the whole nuclear genome) and the proportion of <i>Mos1</i> alleles per chromosome reported in a previous study <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0030482#pone.0030482-Granger1" target="_blank">[5]</a>, and the 10,858 alleles obtained in the current project (black and red circles, respectively). The outliers, concerning chromosomes I and V, from the previous study are highlighted with lines. (B) Distribution of distances from one <i>Mos1</i> allele to the next, in a 5′ to 3′ direction along each chromosome. The graph shows the cumulative percentage of alleles that are separated by less than the indicated distance. (C) Concentration of <i>Mos1</i> alleles at the extreme right end of chromosome I (length 15,072,423 bp). The separation of the allele numbers indicates that almost all the alleles were generated independently, except in two cases (ttTi2276 and ttTi2284; ttTi13453 and ttTi13460), highlighted by an asterisk. This region was also preferentially targeted during the previous study as reflected by the presence of several cxTi alleles.</p