Significant genetic differentiation between Poland and Germany follows present-day political borders, as revealed by Y-chromosome analysis

To test for human population substructure and to investigate human population history we have analysed Y-chromosome diversity using seven microsatellites (Y-STRs) and ten binary markers (Y-SNPs) in samples from eight regionally distributed populations from Poland (n=913) and 11 from Germany (n=1,215). Based on data from both Y-chromosome marker systems, which we found to be highly correlated (r=0.96), and using spatial analysis of the molecular variance (SAMOVA), we revealed statistically significant support for two groups of populations: (1) all Polish populations and (2) all German populations. By means of analysis of the molecular variance (AMOVA) we observed a large and statistically significant proportion of 14% (for Y-SNPs) and 15% (for Y-STRs) of the respective total genetic variation being explained between both countries. The same population differentiation was detected using Monmoniers algorithm, with a resulting genetic border between Poland and Germany that closely resembles the course of the political border between both countries. The observed genetic differentiation was mainly, but not exclusively, due to the frequency distribution of two Y-SNP haplogroups and their associated Y-STR haplotypes: R1a1*, most frequent in Poland, and R1*(xR1a1), most frequent in Germany. We suggest here that the pronounced population differentiation between the two geographically neighbouring countries, Poland and Germany, is the consequence of very recent events in human population history, namely the forced human resettlement of many millions of Germans and Poles during and, especially, shortly after World War II. In addition, our findings have consequences for the forensic application of Y-chromosome markers, strongly supporting the implementation of population substructure into forensic Y chromosome databases, and also for genetic association studies.     

Role of integrin-linked kinase in regulating phosphorylation of Akt and fibroblast survival in type I collagen matrices through a beta1 integrin viability signaling pathway

A beta1 integrin phosphatidylinositol 3-kinase/Akt pathway regulates fibroblast survival in collagen matrices. When fibroblasts attach to collagen, Akt becomes phosphorylated, providing a survival signal. In contrast, in response to mechanical forces generated during collagen contraction, Akt is dephosphorylated and fibroblasts undergo apoptosis. The kinase(s) responsible for regulating Akt phosphorylation in response to matrix-derived mechanical signals are unclear. Integrin-linked kinase (ILK) is associated with the beta1 integrin in the focal adhesion complex and as such is a candidate kinase that may regulate Akt phosphorylation and fibroblast viability. Nevertheless, there is no direct evidence that matrix-derived mechanical forces regulate cell viability by modulating ILK activity. Here, we show that ILK activity decreased in response to collagen matrix contraction, which correlated with Akt dephosphorylation and induction of fibroblast apoptosis. In contrast, enforced activation of beta1 integrin by activating antibody preserved ILK and Akt activity during collagen matrix contraction, and this is associated with protection from collagen contraction-induced apoptosis. Knock-down of ILK by small, interfering RNA (siRNA) attenuated Akt phosphorylation in response to ligation of beta1 integrin by collagen or activating antibody and enhanced fibroblast apoptosis in response to collagen contraction. Kinase dead ILK attenuated Akt phosphorylation and enhanced fibroblast apoptosis, whereas hyperactive and wild type ILK augmented Akt phosphorylation and protected fibroblasts from apoptosis. Constitutively active Akt preserved Akt activity and rescued ILK siRNA-treated fibroblasts from collagen contraction-induced apoptosis. These data establish that matrix-derived mechanical forces sensed by beta1 integrin are capable of modulating ILK activity which regulates fibroblast viability via an Akt-dependent mechanism.     

High-resolution identification of chromosomal abnormalities using oligonucleotide arrays containing 116,204 SNPs

Mutation of the human genome ranges from single base-pair changes to whole-chromosome aneuploidy. Karyotyping, fluorescence in situ hybridization, and comparative genome hybridization are currently used to detect chromosome abnormalities of clinical significance. These methods, although powerful, suffer from limitations in speed, ease of use, and resolution, and they do not detect copy-neutral chromosomal aberrations--for example, uniparental disomy (UPD). We have developed a high-throughput approach for assessment of DNA copy-number changes, through use of high-density synthetic oligonucleotide arrays containing 116,204 single-nucleotide polymorphisms, spaced at an average distance of 23.6 kb across the genome. Using this approach, we analyzed samples that failed conventional karyotypic analysis, and we detected amplifications and deletions across a wide range of sizes (1.3-145.9 Mb), identified chromosomes containing anonymous chromatin, and used genotype data to determine the molecular origin of two cases of UPD. Furthermore, our data provided independent confirmation for a case that had been misinterpreted by karyotype analysis. The high resolution of our approach provides more-precise breakpoint mapping, which allows subtle phenotypic heterogeneity to be distinguished at a molecular level. The accurate genotype information provided on these arrays enables the identification of copy-neutral loss-of-heterozygosity events, and the minimal requirement of DNA (250 ng per array) allows rapid analysis of samples without the need for cell culture. This technology overcomes many limitations currently encountered in routine clinical diagnostic laboratories tasked with accurate and rapid diagnosis of chromosomal abnormalities.     

Synaptotagmins I and II act as nerve cell receptors for botulinum neurotoxin G

Botulinum neurotoxins (BoNTs) induce muscle paralysis by selectively entering cholinergic motoneurons and subsequent specific cleavage of core components of the vesicular fusion machinery. Complex gangliosides are requisite for efficient binding to neuronal cells, but protein receptors are critical for internalization. Recent work evidenced that synaptotagmins I and II can function as protein receptors for BoNT/B (Dong, M., Richards, D. A., Goodnough, M. C., Tepp, W. H., Johnson, E. A., and Chapman, E. R. (2003) J. Cell Biol. 162, 1293-1303). Here, we report the protein receptor for a second BoNT serotype. Like BoNT/B, BoNT/G employs synaptotagmins I and II to enter phrenic nerve cells. Using pull-down assays we show that only BoNT/G, but neither the five remaining BoNTs nor tetanus neurotoxin, interacts with synaptotagmins I and II. In contrast to BoNT/B, interactions with both isoforms are independent of the presence of gangliosides. Peptides derived from the luminal domain of synaptotagmin I and II are capable of blocking the neurotoxicity of BoNT/G in phrenic nerve preparations. Pull-down and neutralization assays further established the membrane-juxtaposed 10 luminal amino acids of synaptotagmins I and II as the critical segment for neurotoxin binding. In addition, we show that the carboxyl-terminal domain of the cell binding fragment of BoNT/B and BoNT/G mediates the interaction with their protein receptor.     

Allele Copy Number and Underlying Pathology Are Associated with Subclinical Severity in Equine Type 1 Polysaccharide Storage Myopathy (PSSM1)

Equine type 1 polysaccharide storage myopathy (PSSM1), a common glycogenosis associated with an R309H founder mutation in the glycogen synthase 1 gene (GYS1), shares pathological features with several human myopathies. In common with related human disorders, the pathogenesis remains unclear in particular, the marked phenotypic variability between affected animals. Given that affected animals accumulate glycogen and alpha-crystalline polysaccharide within their muscles, it is possible that physical disruption associated with the presence of this material could exacerbate the phenotype. The aim of this study was to compare the histopathological changes in horses with PSSM1, and specifically, to investigate the hypothesis that the severity of underlying pathology, (e.g. vacuolation and inclusion formation) would (1) be higher in homozygotes than heterozygotes and (2) correlate with clinical severity. Resting and post-exercise plasma creatine kinase (CK) and aspartate aminotransferase (AST) enzyme activity measurements and muscle pathology were assessed in matched cohorts of PSSM1 homozygotes, heterozygotes or control horses. Median (interquartile range (IR)) resting CK activities were 364 (332–764) U/L for homozygotes, 301 (222–377) U/L for heterozygotes and 260 (216–320) U/L for controls, and mean (+/− SD) AST activity for homozygotes were 502 (+/116) U/L, for heterozygotes, 357 (+/−92) U/L and for controls, 311 (+/−64) U/L and were significantly different between groups (P = 0.04 and P = 0.01 respectively). Resting plasma AST activity was significantly associated with the severity of subsarcolemmal vacuolation (rho = 0.816; P = 0.01) and cytoplasmic inclusions (rho = 0.766; P = 0.01). There were fewer type 2× and more type 2a muscle fibres in PSSM1-affected horses. Our results indicate that PSSM1 has incomplete dominance. Furthermore, the association between plasma muscle enzyme activity and severity of underlying pathology suggests that physical disruption of myofibres may contribute to the myopathic phenotype. This work provides insight into PSSM1 pathogenesis and has implications for related human glycogenoses.     

Synthesis and biological activity of -tyrosine-based PPARγ agonists with reduced molecular weight

A series of PPARγ agonists were synthesized from -tyrosine that incorporated low molecular weight N-substituents. The most potent analogue, pyrrole (Scheme 1 and Scheme 2), demonstrated a K_i of 6.9 nM and an EC₅₀ of 4.7 nM in PPARγ binding and functional assays, respectively. Pyrrole (Scheme 1 and Scheme 2), which is readily synthesized from -tyrosine methyl ester in four steps, also demonstrated in vivo activity in a rodent model of Type 2 diabetes.     

Über Sensible Perioden für Die Auslösung Von Hitze-Modifikationen Bei Drosophila Und Die Beziehungen Zwischen Modifikationen Und Mutationen

Molecular Genetics and Genomics -