Evidence for gene duplication forming similar binding folds for NAD(P)H and FAD in pyridine nucleotide-dependent flavoenzymes

AbstractFor pyridine nucleotide-dependent flavoezymes, binding both FAD and NAD(P)H on a single amino-acids chain, we have found a high degree of internal sequence similarity for certain regions of FAD and NAD (P)H binding portions of the chain for any given protein. This was the case for a range of enzymes classes, including disulphide oxidoreductases (such as glutathione reductase, trypanothione reductase, lipoamide dehydrogenase, mercuric reductase), mono- and dioxygenases, nitrite reductaSE, alkyl hydroperoxidase and NADH dehydrogenase from E. coli. This provides strong support for gene duplication as the origin of at least part of the FAD and NAD(P)H recognising domains of such enzymes

The effect of deletions and reduplications on the expression of human α and ζ globin genes

A number of deletions have been documented among the non-α globin genes of man that are associated with repression of residual 3' genes. Opportunities to pursue similar structure function correlations among the α and ζ globin genes have been less frequent. The most common deletion observed has been that of one of the two a globin genes in cis on chromosome 16 due to the -3.7 type of α-Thal-2. It is found in 33% of 345 Black children in the Pediatric Sickle Cell Clinics of our center. The same α-Thal as semi a-2 condition has been documented by gene mapping or family studies or both among 48 newborn and adult Hb G Philadelphia (Hb G) heterozygotes from the Black population of the Southeastern USA and Caucasians from Northern Italy. Hb G is rather unique among hemoglobin variants because it has been observed in association with a diversity of a globin genotypes having 3, 2, 1 or O additional αA globin genes in cis or in trans to the αG gene. Quantification of the αG globin produced from each α6 globin qene in probands with the ααG/αα, -αG/αα, -αG/-α, -αG/-αG and -αG/-- genotypes show that there is considerable derepression of the αG globin gene in cis to the -3.7 α-Thal-2 deletion and of the αA genes in trans.peer-reviewe

Diphthamide modification of eEF2 requires a J-domain protein and is essential for normal development

The intracellular target of diphtheria toxin is a modified histidine residue, diphthamide, in the translation elongation factor, eEF2. This enigmatic modification occurs in all eukaryotes, and is produced in yeast by the action of five gene products, DPH1 to DPH5. Sequence homologues of these genes are present in all sequenced eukaryotic genomes and in higher eukaryotes there is functional evidence for DPH1, 2, 3, and 5 acting in diphthamide biosynthesis. We have identified a mouse mutant in the remaining gene, Dph4. Cells derived from homozygous mutant embryos lack the diphthamide modification of EF2 and are resistant to killing by diphtheria toxin. Reporter-tagged DPH4 protein localizes to the cytoskeleton, in contrast to the localization of DPH1, and consistent with evidence that DPH4 is not part of a proposed complex containing DPH1, 2 and 3. Mice homozygous for the mutation are retarded in growth and development and almost always die before birth. Those that survive long enough have preaxial polydactyly, a duplication of digit 1 of the hind foot. This same defect is seen in embryos homozygous for mutation of DPH1, suggesting that lack of diphthamide on eEF2 could result in translational failure of specific proteins, rather than a generalized translation downregulation

Draft Nuclear Genome, Complete Chloroplast Genome, and Complete Mitochondrial Genome for the Biofuel/ Bioproduct Feedstock Species Scenedesmus obliquus Strain DOE0152z

The green alga Scenedesmus obliquus is an emerging platform species for the industrial production of biofuels. Here, we report the draft assembly and annotation for the nuclear, plastid, and mitochondrial genomes of S. obliquus strain DOE0152z

The occurrence of α chain gene deletions and triplications among pediatric Hb S homozygotes

Approximately 40% of more than 100 young Hb S homozygotes attending the Pediatric Clinic of the Comprehensive Sickle Cell Center of the Medical College of Georgia in Augusta have an associated α-thalassemia-2 (α-thal-2) heteroztgosity, i.e. the -α/-α; βs/βs condition, or homozygosity, i.e. the -α/-α; βs/βs condition. These conditions are documented by pulse incubations of peripheral blood reticulocytes and by gene mapping using recombinant DNA probes. All α-thal-2 deletions are associated with a 16 Kb Bgl II α chain DNA fragment which arises from a deletion of the 3' end of the α2 gene, the 5' end of the α1 gene and includes the intergenic DNA. Fusion of the residual 3' and 5' ends of the α2 and α1 genes results in a single active a chain gene, i.e. the -3.7 Kb or Rightward type of deletion. Its 3' sequences belong to the α1 gene. The homozygosity for the condition and Hb S is characterized by higher Hb levels without an accompanying increase of Hb F percentages; a distinct microcytosis and hypochromia; splenomegaly and decreased α/non-α values.peer-reviewe

The tumor suppressor protein OPCML potentiates anti-EGFR and anti-HER2 targeted therapy in HER2-positive ovarian and breast cancer.

OPCML is a tumor suppressor gene that is frequently inactivated in ovarian cancer and many other cancers by somatic methylation. We have previously shown that OPCML exerts its suppressor function by negatively regulating a spectrum of receptor tyrosine kinases (RTKs), such as ErbB2/HER2, FGFR1 and EphA2, thus attenuating their related downstream signaling. The physical interaction of OPCML with this defined group of RTKs is a prerequisite for their downregulation. Overexpression/gene amplification of EGFR and HER2 is a frequent event in multiple cancers including ovarian and breast cancers. Molecular therapeutics against EGFR/HER2 or EGFR only, such as lapatinib and erlotinib respectively, were developed to target these receptors but resistance often occurs in relapsing cancers. Here we show that, though OPCML interacts only with HER2 and not with EGFR, the interaction of OPCML with HER2 disrupts the formation of the HER2-EGFR heterodimer and this translates into a better response to both lapatinib and erlotinib in HER2-expressing ovarian and breast cancer cell lines. Also, we show that high OPCML expression is associated with better response to lapatinib therapy in breast cancer patients and better survival in HER2-overexpressing ovarian cancer patients, suggesting that OPCML co-therapy could be a valuable sensitizing approach to RTK inhibitors

Inhibition of macropinocytosis blocks antigen presentation of type II collagen in vitro and in vivo in HLA-DR1 transgenic mice

Professional antigen-presenting cells, such as dendritic cells, macrophages and B cells have been implicated in the pathogenesis of rheumatoid arthritis, constituting a possible target for antigen-specific immunotherapy. We addressed the possibility of blocking antigen presentation of the type II collagen (CII)-derived immunodominant arthritogenic epitope CII(259–273 )to specific CD4 T cells by inhibition of antigen uptake in HLA-DR1-transgenic mice in vitro and in vivo. Electron microscopy, confocal microscopy, subcellular fractionation and antigen presentation assays were used to establish the mechanisms of uptake, intracellular localization and antigen presentation of CII by dendritic cells and macrophages. We show that CII accumulated in membrane fractions of intermediate density corresponding to late endosomes. Treatment of dendritic cells and macrophages with cytochalasin D or amiloride prevented the intracellular appearance of CII and blocked antigen presentation of CII(259–273 )to HLA-DR1-restricted T cell hybridomas. The data suggest that CII was taken up by dendritic cells and macrophages predominantly via macropinocytosis. Administration of amiloride in vivo prevented activation of CII-specific polyclonal T cells in the draining popliteal lymph nodes. This study suggests that selective targeting of CII internalization in professional antigen-presenting cells prevents activation of autoimmune T cells, constituting a novel therapeutic strategy for the immunotherapy of rheumatoid arthritis

2D Semiconductor Nonlinear Plasmonic Modulators

A plasmonic modulator is a device that controls the amplitude or phase of propagating plasmons. In a pure plasmonic modulator, the presence or absence of a pump plasmonic wave controls the amplitude of a probe plasmonic wave through a channel. This control has to be mediated by an interaction between disparate plasmonic waves, typically requiring the integration of a nonlinear material. In this work, we demonstrate the first 2D semiconductor nonlinear plasmonic modulator based on a WSe2 monolayer integrated on top of a lithographically defined metallic waveguide. We utilize the strong coupling between the surface plasmon polaritons, SPPs, and excitons in the WSe2 to give a 73 percent change in transmission through the device. We demonstrate control of the propagating SPPs using both optical and SPP pumps, realizing the first demonstration of a 2D semiconductor nonlinear plasmonic modulator, with a modulation depth of 4.1 percent, and an ultralow switching energy estimated to be 40 aJ