Evaluation of RGS4 as a candidate gene for schizophrenia.

Several studies have suggested that the regulator of G-protein signaling 4 (RGS4) may be a positional and functional candidate gene for schizophrenia. Three single nucleotide polymorphisms (SNP) located at the promoter region (SNP4 and SNP7) and the intron 1 (SNP18) of RGS4 have been verified in different ethnic groups. Positive results have been reported in these SNPs with different numbers of SNP combinatory haplotypes. In this study, these three SNP markers were genotyped in 218 schizophrenia pedigrees of Taiwan (864 individuals) for association analysis. Among these three SNPs, neither SNP4, SNP7, SNP18 has shown significant association with schizophrenia in single locus association analysis, nor any compositions of the three SNP haplotypes has shown significantly associations with the DSM-IV diagnosed schizophrenia. Our results fail to support the RGS4 as a candidate gene for schizophrenia when evaluated from these three SNP markers.     

Brachydactyly type A3 is caused by a novel 13 bp HOXD13 frameshift deletion in a Chinese family

Brachydactyly type A (BDA) is defined as short middle phalanges of the affected digits and is subdivided into four types (BDA1‐4). To date, the molecular cause is unknown. However, there is some evidence that pathogenic variants of HOXD13 could be associated with BDA3 and BDA4. Here, we report a Chinese autosomal dominant BDA3 pedigree with a novel HOXD13 mutation. The affected individuals presented with an obviously shorter fifth middle phalanx. The radial side of the middle phalanx was shorter than the ulnar side, and the terminal phalanx of the fifth finger inclined radially and formed classical clinodactyly. Interestingly, the index finger was normal. The initial diagnosis was BDA3. However, the distal third and fourth middle phalanges were also slightly affected, resulting in mild radial clinodactyly. Both feet showed shortening of the middle phalanges, which were fused to the distal phalanges of the second to the fifth toes, as reported in BDA4. Therefore, this pedigree had combined BDA3 and atypical BDA4. By direct sequencing, a 13 bp deletion within exon 1 of HOXD13 (NM_000523.4: c.708_720del13; NP_000514.2: p.Gly237fs) was identified. The 13 bp deletion resulted in a frameshift and premature termination of HOXD13. This study provides further evidences that variants in HOXD13 cause BDA3‐BDA4 phenotypes.     

<Emphasis Type="Italic">GPC5</Emphasis> is a possible target for the 13q31-q32 amplification detected in lymphoma cell lines

Comparative genomic hybridization (CGH) analyses have detected gains of copy number on 13q, especially at 13q31-q32, in cell lines and primary cases of various types of lymphoma. Since amplification of chromosomal DNA is one of the mechanisms that can activate tumor-associated genes, and because 13q amplification had been reported in various other types of tumors as well, we attempted to define by fluorescence in situ hybridization (FISH) a common region at 13q31-q32 in which to explore genes that might be targets for the amplification events. Although the commonly amplified region we defined was relatively large (approximately 4 Mb), only one true gene, GPC5, was found there. GPC5 was over-expressed in lymphoma cell lines that had shown amplification, in comparison with those that had not. Our findings suggest that GPC5 is a likely target for amplification, and that over-expression of this gene may contribute to development and/or progression of lymphomas and other tumors.     

Self-assembled biomimetic monolayers using phospholipid-containing disulfides

Several phospholipid-based disulfide molecules were synthesized and attached onto the gold-coated silicon wafer using the self-assembling method. The syntheses of these surface-modifying agents were conducted by introducing bromoethylphosphorate (PBr), phosphorylcholine (PC) or phosphorylethanolamine (PE) groups on the terminals of a dialkyl disulfide. After disulfides adsorption onto gold substrate surfaces, the composition, the film thickness, and the conformational order of self-assembled monolayer surfaces were explored and discussed in detail based on reflection-absorption infrared spectroscopy, contact angle measurement, Auger electron spectroscopy, X-ray photoelectron spectroscopy, and so on. The monolayer having the PBr end group could also be converted to a PC surface by treating with trimethylamine. The model functional surfaces of Au-SC11-PC, -PE, -PBr, -OH or corresponding mixed layers were used to mimic biomembrane surfaces. The monolayer having PC groups was found to reduce fibrinogen adsorption as evaluated from protein adsorption experiments using quartz crystal microbalance. It also showed relatively low platelet adherence compare to the glass, PBr and PE surfaces. The cell viability test also revealed that the PC surface displayed lower cytotoxicity than other surfaces.     

Characterization of 19 disease-associated missense mutations in the regulatory domain of the cystic fibrosis transmembrane conductance regulator

In order to gain a better insight into the structure and function of the regulatory domain (RD) of the cystic fibrosis transmembrane conductance regulator (CFTR) protein, 19 RD missense mutations that had been identified in patients were functionally characterized. Nine of these (I601F, L610S, A613T, D614G, I618T, L619S, H620P, G628R and L633P) resulted in aberrant processing. No or a very small number of functional CFTR proteins will therefore appear at the cell membrane in cells expressing these mutants. These mutations were clustered in the N- terminal part of the RD, suggesting that this subdomain has a folding pattern that is very sensitive to amino acid changes. Mutations that caused no aberrant processing were further characterized at the electrophysiological level. First, they were studied at the whole cell level in Xenopus laevis oocytes. Mutants that induced a whole cell current that was significantly different from wild-type CFTR were subsequently analysed at the single channel level in COS1 cells transiently expressing the different mutant and wild-type proteins. Three mutant chloride channels, G622D, R792G and E822K CFTR, were characterized by significantly lower intrinsic chloride channel activities compared with wild-type CFTR. Two mutations, H620Q and A800G, resulted in increased intrinsic chloride transport activities. Finally, T665S and E826K CFTR had single channel properties not significantly different from wild-type CFTR.      

The effect of automated landmark identification on morphometric analyses

Morphometric analysis of anatomical landmarks allows researchers to identify specific morphological differences between natural populations or experimental groups, but manually identifying landmarks is time‐consuming. We compare manually and automatically generated adult mouse skull landmarks and subsequent morphometric analyses to elucidate how switching from manual to automated landmarking will impact morphometric analysis results for large mouse (Mus musculus) samples (n = 1205) that represent a wide range of ‘normal’ phenotypic variation (62 genotypes). Other studies have suggested that the use of automated landmarking methods is feasible, but this study is the first to compare the utility of current automated approaches to manual landmarking for a large dataset that allows the quantification of intra‐ and inter‐strain variation. With this unique sample, we investigated how switching to a non‐linear image registration‐based automated landmarking method impacts estimated differences in genotype mean shape and shape variance‐covariance structure. In addition, we tested whether an initial registration of specimen images to genotype‐specific averages improves automatic landmark identification accuracy. Our results indicated that automated landmark placement was significantly different than manual landmark placement but that estimated skull shape covariation was correlated across methods. The addition of a preliminary genotype‐specific registration step as part of a two‐level procedure did not substantially improve on the accuracy of one‐level automatic landmark placement. The landmarks with the lowest automatic landmark accuracy are found in locations with poor image registration alignment. The most serious outliers within morphometric analysis of automated landmarks displayed instances of stochastic image registration error that are likely representative of errors common when applying image registration methods to micro‐computed tomography datasets that were initially collected with manual landmarking in mind. Additional efforts during specimen preparation and image acquisition can help reduce the number of registration errors and improve registration results. A reduction in skull shape variance estimates were noted for automated landmarking methods compared with manual landmarking. This partially reflects an underestimation of more extreme genotype shapes and loss of biological signal, but largely represents the fact that automated methods do not suffer from intra‐observer landmarking error. For appropriate samples and research questions, our image registration‐based automated landmarking method can eliminate the time required for manual landmarking and have a similar power to identify shape differences between inbred mouse genotypes.     

A p74 common gamma receptor chain isoform facilitates IL-2 and IL-15 responses by the myelomonocytic cell line Tf-1beta2

Functional forms of the IL-2, IL-4, IL-7, IL-9, and IL-15 receptors require the gamma c receptor component. We have described previously a myeloid cell line called Tf-1beta, which binds IL-2 with intermediate-affinity and proliferates in response to IL-2. In this study, we characterize gamma c expression on Tf-1beta2 cells, a derivative of Tf-1beta cells stimulated exclusively with IL-2. Although Tf-1beta2 cells bind IL-2 with intermediate-affinity and proliferate in response to IL-2, this cell line does not express the p64 gamma c chain at the protein level. This result was surprising because prior studies suggest these cells should not be expected to proliferate in response to IL-2 or IL-15 in the absence of the p64 gamma c chain. A p74 protein was detected by western blot following immunoprecipitation with an anti-gamma c polyclonal antibody, and a p74 protein was identified consistently in complex with IL-2 and IL-15 on these cells. However, the gamma c gene in these Tf-1beta2 cells shows no evidence of mutation by sequence analysis. Furthermore, inhibition of glycosylation of these Tf-1beta2 cells by tunicamycin treatment yields a standard 39-kDa molecule recognized on western blot with anti-gamma c antibody, as seen for the standard 64-kDa isoform of gamma c. These results demonstrate that a 74-kDa gamma c receptor isoform was involved in the response of the Tf-1beta2 cells to cytokines which normally interact with the 64-kDa gamma c chain.