Allelic variation of high-molecular-weight glutenin genes in bread wheat

The composition and quantity of high-molecular-weight glutenin subunits plays an important role in determining the bread-making quality of wheat. Molecular-genetic analysis of allelic composition of high-molecular-weight glutenin genes in 102 bread wheat cultivars and lines from different geographical regions was conducted. Three alleles at the Glu-A1 locus, nine alleles at the Glu-B1 locus, and two alleles at the Glu-D1 locus were identified. Among the investigated cultivars and lines, 21 were characterized by intracultivar polymorphism. High allelic variation of high-molecular-weight glutenin subunit genes was shown for the collection: 21 and 9 combinations were defined in monomorphic and polymorphic cultivars and lines, respectively. However, the major part of the collection (66.7%) contained four allelic combinations: Glu-A1b Glu-B1c Glu-D1d, Glu-A1b Glu-B1c Glu-D1-2a, Glu-A1a Glu-B1c Glu-D1d, and Glu-A1b Glu-B1c Glu-D1d/Glu-D1-2a. Fourteen cultivars of bread wheat were selected, and they were characterized by a favorable allelic composition of Glu-1 loci.     

An Enhanced Immune Response of Mclk1 +/? Mutant Mice Is Associated with Partial Protection from Fibrosis,Cancer and the Development of Biomarkers of Aging

The immune response is essential for survival by destroying microorganisms and pre-cancerous cells. However, inflammation, one aspect of this response, can result in short- and long-term deleterious side-effects. Mclk1 ^+/− mutant mice can be long-lived despite displaying a hair-trigger inflammatory response and chronically activated macrophages as a result of high mitochondrial ROS generation. Here we ask whether this phenotype is beneficial or simply tolerated. We used models of infection by Salmonella serovars and found that Mclk1 ^+/− mutants mount a stronger immune response, control bacterial proliferation better, and are resistant to cell and tissue damage resulting from the response, including fibrosis and types of oxidative damage that are considered to be biomarkers of aging. Moreover, these same types of tissue damage were found to be low in untreated 23 months-old mutants. We also examined the initiation of tumour growth after transplantation of mouse LLC1 carcinoma cells into Mclk1 ^+/− mutants, as well as during spontaneous tumorigenesis in Mclk1 ^+/− Trp53 ^+/− double mutants. Tumour latency was increased by the Mclk1 ^+/− genotype in both models. Furthermore, we used the transplantation model to show that splenic CD8+ T lymphocytes from Mclk1 ^+/− graft recipients show enhanced cytotoxicity against LLC1 cells in vitro. Mclk1 ^+/− mutants thus display an association of an enhanced immune response with partial protection from age-dependent processes and from pathologies similar to those that are found with increased frequency during the aging process. This suggests that the immune phenotype of these mutants might contribute to their longevity. We discuss how these findings suggest a broader view of how the immune response might impact the aging process.     

Resistance to Diet-Induced Obesity and Associated Metabolic Perturbations in Haploinsufficient Monocarboxylate Transporter 1 Mice

The monocarboxylate transporter 1 (MCT1 or SLC16A1) is a carrier of short-chain fatty acids, ketone bodies, and lactate in several tissues. Genetically modified C57BL/6J mice were produced by targeted disruption of the mct1 gene in order to understand the role of this transporter in energy homeostasis. Null mutation was embryonically lethal, but MCT1 ^+/− mice developed normally. However, when fed high fat diet (HFD), MCT1 ^+/− mice displayed resistance to development of diet-induced obesity (24.8% lower body weight after 16 weeks of HFD), as well as less insulin resistance and no hepatic steatosis as compared to littermate MCT1 ^+/+ mice used as controls. Body composition analysis revealed that reduced weight gain in MCT1 ^+/− mice was due to decreased fat accumulation (50.0% less after 9 months of HFD) notably in liver and white adipose tissue. This phenotype was associated with reduced food intake under HFD (12.3% less over 10 weeks) and decreased intestinal energy absorption (9.6% higher stool energy content). Indirect calorimetry measurements showed ∼ 15% increase in O₂ consumption and CO₂ production during the resting phase, without any changes in physical activity. Determination of plasma concentrations for various metabolites and hormones did not reveal significant changes in lactate and ketone bodies levels between the two genotypes, but both insulin and leptin levels, which were elevated in MCT1 ^+/+ mice when fed HFD, were reduced in MCT1 ^+/− mice under HFD. Interestingly, the enhancement in expression of several genes involved in lipid metabolism in the liver of MCT1 ^+/+ mice under high fat diet was prevented in the liver of MCT1 ^+/− mice under the same diet, thus likely contributing to the observed phenotype. These findings uncover the critical role of MCT1 in the regulation of energy balance when animals are exposed to an obesogenic diet.     

Oxygenation properties and oxidation rates of mouse hemoglobins that differ in reactive cysteine content

House mice (genus Mus) harbor extensive allelic variation at two tandemly duplicated genes that encode the β-chain subunits of adult hemoglobin (Hb). Alternative haplotypes differ in the level of sequence divergence between the two β-globin gene duplicates: the Hbb^d and Hbb^p haplotypes harbor two structurally distinct β-globin genes, whereas the Hbb^s haplotype harbors two β-globin duplicates that are identical in sequence. One especially salient difference between the s-type Hbs relative to the d- and p-type Hbs relates to the number of reactive β-chain cysteine residues. In addition to the highly conserved cysteine residue at β93, the d- and p-type Hbs contain an additional reactive cysteine residue at β13. To assess the functional consequences of allelic variation in β-globin cysteine content, we measured O₂-binding properties and H₂O₂-induced oxidation rates of mono- and dicysteinyl β-Hbs from 4 different inbred strains of mice: C57BL/6J, BALB/cJ, MSM/Ms, and CAROLI/EiJ. The experiments revealed that purified Hbs from the various mouse strains did not exhibit substantial variation in O₂-binding properties, but s-type Hb (which contains a single reactive β-chain cysteine residue) was far more readily oxidized to Fe^3 + metHb by H₂O₂ than other mouse Hbs that contain two reactive β-chain cysteine residues. These results suggest that the possession of an additional reactive cysteine residue may protect against metHb formation under oxidizing conditions. The allelic differences in β-globin cysteine content could affect aspects of redox signaling and oxidative/nitrosative stress responses that are mediated by Hb-S-nitrosylation and Hb-S-glutathionylation pathways.     

A mouse model for Li-Fraumeni-Like Syndrome with cardiac angiosarcomas associated to POT1 mutations

The shelterin protein POT1 has been found mutated in many different familial and sporadic cancers, however, no mouse models to understand the pathobiology of these mutations have been developed so far. To address the molecular mechanisms underlying the tumorigenic effects of POT1 mutant proteins in humans, we have generated a mouse model for the human POT1^R117C mutation found in Li-Fraumeni-Like families with cases of cardiac angiosarcoma by introducing this mutation in the Pot1a endogenous locus, knock-in for Pot1a^R117C. We find here that both mouse embryonic fibroblasts (MEFs) and tissues from Pot1a^+/ki mice show longer telomeres than wild-type controls. Longer telomeres in Pot1a^+/ki MEFs are dependent on telomerase activity as they are not found in double mutant Pot1a^+/ki Tert^-/- telomerase-deficient MEFs. By using complementation assays we further show that POT1a pR117C exerts dominant-negative effects at telomeres. As in human Li-Fraumeni patients, heterozygous Pot1a^+/ki mice spontaneously develop a high incidence of angiosarcomas, including cardiac angiosarcomas, and this is associated to the presence of abnormally long telomeres in endothelial cells as well as in the tumors. The Pot1a^+/R117C mouse model constitutes a useful tool to understand human cancers initiated by POT1 mutations.     

Elucidation of Molecular Identity of the W3 Locus and Its Implication in Determination of Flower Colors in Soybean

The wide range of flower colors in soybean is controlled by six independent loci (W1, W2, W3, W4, Wm, and Wp). Among these loci, mutations in the W3 locus under the w4 allelic background (i.e., w3w4) produce near-white flowers, while the W3w4 genotype produces purple throat flowers. Although a gene encoding dihydroflavonol 4-reductase, DFR1, has been known to be closely associated with the W3 locus, its molecular identity has not yet been characterized. In the present study, we aimed to determine whether DFR1 is responsible for allelic variations in the W3 locus. On the basis of the sequence of a DFR probe, Glyma.14G072700 was identified as a candidate gene for DFR1, and nucleotide sequences of Glyma.14G072700 from cultivars with previously validated genotypes for the W3 locus were determined. As a result, a number of nucleotide polymorphisms, mainly single-base substitutions, between both coding and 5′-upstream region sequences of the W3 and w3 alleles were identified. Among them, an indel of 311-bp in the 5′-upstream region was noteworthy, since the Glyma.14G072700 in all the w3 alleles examined contained the indel, whereas that in all the W3 alleles did not; the former was barely expressed, but the latter was well expressed. These results suggest that Glyma.14G072700 is likely to correspond to DFR1 for the W3 locus and that its expression patterns may lead to allelic color phenotypes of W3 and w3 alleles under the w4 allelic background.     

Effect of Bcl11b genotypes and gamma-radiation on the development of mouse thymic lymphomas

Bcl11b is a haploinsufficient tumor suppressor gene and expressed in many tissues such as thymus, brain and skin. Irradiated Bcl11b^+/− heterozygous mice mostly develop thymic lymphomas, but the preference of Bcl11b inactivation for thymic lymphomas remains to be addressed. We produced Bcl11b^+/− heterozygous and Bcl11b wild-type mice of p53^+/− background and compared their incidence of γ-ray induced thymic lymphomas. Majority of the tumors in p53^+/− mice were skin tumors, and only 5 (36%) of the 14 tumors were thymic lymphomas. In contrast, Bcl11b^+/−p53^+/− doubly heterozygous mice developed thymic lymphomas at the frequency of 27 (79%) of the 34 tumors developed (P = 0.008). This indicates the preference of Bcl11b impairment for thymic lymphoma development. We also analyzed loss of the wild-type alleles in the 27 lymphomas, a predicted consequence given by γ-irradiation. However, the loss frequency was low, only six (22%) for Bcl11b and five (19%) for p53. The frequencies did not differ from those of spontaneously developed thymic lymphomas in the doubly heterozygous mice, though the latency of lymphoma development markedly differed between them. This suggests that the main contribution of irradiation at least in those mice is not for the tumor initiation by inducing allelic losses but probably for the promotion of thymic lymphoma development.     

Reduced Life- and Healthspan in Mice Carrying a Mono-Allelic BubR1 MVA Mutation

Mosaic Variegated Aneuploidy (MVA) syndrome is a rare autosomal recessive disorder characterized by inaccurate chromosome segregation and high rates of near-diploid aneuploidy. Children with MVA syndrome die at an early age, are cancer prone, and have progeroid features like facial dysmorphisms, short stature, and cataracts. The majority of MVA cases are linked to mutations in BUBR1, a mitotic checkpoint gene required for proper chromosome segregation. Affected patients either have bi-allelic BUBR1 mutations, with one allele harboring a missense mutation and the other a nonsense mutation, or mono-allelic BUBR1 mutations combined with allelic variants that yield low amounts of wild-type BubR1 protein. Parents of MVA patients that carry single allele mutations have mild mitotic defects, but whether they are at risk for any of the pathologies associated with MVA syndrome is unknown. To address this, we engineered a mouse model for the nonsense mutation 2211insGTTA (referred to as GTTA) found in MVA patients with bi-allelic BUBR1 mutations. Here we report that both the median and maximum lifespans of the resulting BubR1 ^+/GTTA mice are significantly reduced. Furthermore, BubR1 ^+/GTTA mice develop several aging-related phenotypes at an accelerated rate, including cataract formation, lordokyphosis, skeletal muscle wasting, impaired exercise ability, and fat loss. BubR1 ^+/GTTA mice develop mild aneuploidies and show enhanced growth of carcinogen-induced tumors. Collectively, these data demonstrate that the BUBR1 GTTA mutation compromises longevity and healthspan, raising the interesting possibility that mono-allelic changes in BUBR1 might contribute to differences in aging rates in the general population.     

Acid Sphingomyelinase Gene Knockout Ameliorates Hyperhomocysteinemic Glomerular Injury in Mice Lacking Cystathionine-β-Synthase

Acid sphingomyelinase (ASM) has been implicated in the development of hyperhomocysteinemia (hHcys)-induced glomerular oxidative stress and injury. However, it remains unknown whether genetically engineering of ASM gene produces beneficial or detrimental action on hHcys-induced glomerular injury. The present study generated and characterized the mice lacking cystathionine β-synthase (Cbs) and Asm mouse gene by cross breeding Cbs^+/− and Asm^+/− mice. Given that the homozygotes of Cbs^−/−/Asm^−/− mice could not survive for 3 weeks. Cbs^+/−/Asm^+/+, Cbs^+/−/Asm^+/− and Cbs^+/−/Asm^−/− as well as their Cbs wild type littermates were used to study the role of Asm^−/− under a background of Cbs^+/− with hHcys. HPLC analysis revealed that plasma Hcys level was significantly elevated in Cbs heterozygous (Cbs^+/−) mice with different copies of Asm gene compared to Cbs^+/+ mice with different Asm gene copies. Cbs^+/−/Asm^+/+ mice had significantly increased renal Asm activity, ceramide production and O₂.⁻ level compared to Cbs^+/+/Asm^+/+, while Cbs^+/−/Asm^−/− mice showed significantly reduced renal Asm activity, ceramide production and O₂.⁻ level due to increased plasma Hcys levels. Confocal microscopy demonstrated that colocalization of podocin with ceramide was much lower in Cbs^+/−/Asm^−/− mice compared to Cbs^+/−/Asm^+/+ mice, which was accompanied by a reduced glomerular damage index, albuminuria and proteinuria in Cbs^+/−/Asm^−/− mice. Immunofluorescent analyses of the podocin, nephrin and desmin expression also illustrated less podocyte damages in the glomeruli from Cbs^+/−/Asm^−/− mice compared to Cbs^+/−/Asm^+/+ mice. In in vitro studies of podocytes, hHcys-enhanced O₂.⁻ production, desmin expression, and ceramide production as well as decreases in VEGF level and podocin expression in podocytes were substantially attenuated by prior treatment with amitriptyline, an Asm inhibitor. In conclusion, Asm gene knockout or corresponding enzyme inhibition protects the podocytes and glomeruli from hHcys-induced oxidative stress and injury.     

An acetylated galactomannoglucan from the stems of Dendrobium nobile Lindl

A water-soluble polysaccharide DNP-W2 composed of glucose, mannose, and galactose in the molar ratio of 6.1:2.9:2.0 had been isolated from the stems of Dendrobium nobile. Its molecular weight was 1.8 × 10⁴ Da determined by HPGPC. Structural features of DNP-W2 were investigated by a combination of chemical and instrumental analysis, including FTIR, GC, GC-MS, periodate oxidation-Smith degradation, methylation analysis, partial acid hydrolysis, and NMR spectroscopy. The results showed that DNP-W2 is a 2-O-acetylgalactomannoglucan and has a backbone consisting of (1→4)-linked β-d-Glcp, (1→6)-linked β-d-Glcp, and (1→4)-linked β-d-Manp, with branches at O-6 of (1→4)-linked β-d-Glcp and β-d-Manp. The branches are composed of α-d-Galp. The acetyl groups are substituted at O-2 of (1→4)-linked Manp. Preliminary tests in vitro reveals that DNP-W2 can stimulate ConA- and LPS-induced T and B lymphocyte proliferation.     

Separation, structure characterization, conformation and immunomodulating effect of a hyperbranched heteroglycan from Radix Astragali

A water soluble polysaccharide (RAP) was isolated and purified from Radix Astragali and its structure was elucidated by monosaccharide composition, partial acid hydrolysis and methylation analysis, and further supported by FT-IR, GC-MS and ¹H and ¹³C NMR spectra, SEM and AFM microscopy. Its average molecular weight was 1334 kDa. It was composed of Rha, Ara, Glc, Gal and GalA in a molar ratio of 0.03:1.00:0.27:0.36:0.30. The backbone consisted of 1,2,4-linked Rhap, α-1,4-linked Glcp, α-1,4-linked GalAp6Me, β-1,3,6-linked Galp, with branched at O-4 of the 1,2,4-linked Rhap and O-3 or O-4 of β-1,3,6-linked Galp. The side chains mainly consisted of α-T-Araf and α-1,5-linked Araf with O-3 as branching points, having trace Glc and Gal. The terminal residues were T-linked Araf, T-linked Glcp and T-linked Galp. Morphology analysis showed that RAP took random coil feature. RAP exhibited significant immunomodulating effects by stimulating the proliferation of human peripheral blood mononuclear cells and enhancing its interleukin production.     

Markers of squamous cell carcinoma in sarco/endoplasmic reticulum Ca ATPase 2 heterozygote mice keratinocytes

A mutation of Atp2a2 gene encoding the sarco/endoplasmic reticulum Ca²⁺-ATPase 2 (SERCA2) causes Darier's disease in human and null mutation in one copy of Atp2a2 leads to a high incidence of squamous cell tumor in a mouse model. In SERCA2 heterozygote (SERCA2^+/−) mice keratinocytes, mechanisms involved in partial depletion of SERCA2 gene and its related tumor induction have not been studied. In this study, we investigated Ca²⁺ signaling and differential gene expression in primary cultured keratinocytes from SERCA2^+/− mice. SERCA2^+/− keratinocytes showed reduced initial increases in intracellular concentration of calcium in response to ATP, a G-protein coupled receptor agonist, and higher store-operated Ca²⁺ entry with the treatment of thapsigargin, an inhibitor of SERCA, compared to wild type kerationcytes. Protein expressions of plasma membrane Ca²⁺ ATPases, NFATc1, phosphorylated ERK, JNK, and phospholipase γ1 were increased in SERCA2^+/− keratinocytes. Using the gene fishing system, we first found in SERCA2^+/− keratinocytes that gene level of tumor-associated calcium signal transducer 1, crystalline αB, procollagen XVIII α1, and nuclear factor I-B were increased. Expression of involucrin, a marker of keratinocyte differentiation, was decreased in SERCA2^+/− keratinocytes. These results suggest that the alterations of Ca²⁺ signaling by SERCA2 haploinsufficiency alternate the gene expression of tumor induction and differentiation in keratinocytes.     

Enzymatically derived aldouronic acids from Cryptomeria japonica arabinoglucuronoxylan

An arabinoglucuronoxylan was extracted from the holocellulose of sugi (Cryptomeria japonica) wood with 10% KOH and subjected to hydrolysis by partially purified xylanase fraction from a commercial cellulase preparation “Meicelase”. Neutral sugars liberated were analyzed by size exclusion chromatography showing the presence of xylooligosaccharides up to xylohexaose. Aldouronic acids liberated were purified by preparative anion exchange chromatography. Their structures were identified by monosaccharide analysis, comparison of their volume distribution coefficients (Dvs) with those of the authentic samples in anion exchange chromatography and ¹H and ¹³C NMR spectroscopy, resulting in the characterization of eight aldouronic acids including acids consisting of two 4-O-Me-α-D-GlcAp residues and 3-5 D-Xyl residues.

1.

Fr. 1-S1: (aldohexaouronic acid, MeGlcA³Xyl₅), O-β-Xylp-(1 → 4)-O-β-D-Xylp-(1 → 4)-[O-(4-O-Me-α-D-GlcAp)-(1 → 2)]-O-β-Xylp-(1 → 4)-O-β-D-Xylp-(1 → 4)-D-Xyl

2.

Fr. 1-S2: (aldopentaouronic acid, MeGlcA³Xyl₄), O-β-Xylp-(1 → 4)-[O-(4-O-Me-α-D-GlcAp)-(1 → 2)]-O-β-D-Xylp-(1 → 4)-O-β-Xylp-(1 → 4)-D-Xyl

3.

Fr. 2-S1: (aldotetraouronic acid, MeGlcA³Xyl₃), O-(4-O-Me-α-D-GlcAp)-(1 → 2)-O-β-D-Xylp-(1 → 4)-O-β-D-Xylp-(1 → 4)-D-Xyl

4.

Fr. 3-S1: (aldotetraouronic acid, GlcA³Xyl₃), O-(α-D-GlcAp)-(1 → 2)-O-β-D-Xylp-(1 → 4)-O-β-Xylp-(1 → 4)-D-Xyl,

5.

Fr. 4-S1: (aldotriouronic acid, GlcA²Xyl₂), O-(4-O-Me-α-D-GlcAp)-(1 → 2)-O-β-D-Xylp-(1 → 4)-D-Xyl

6.

Fr. 4-S2: (MeGlc⁴MeGlcA³Xyl₅), O-β-D-Xylp-(1 → 4)-[O-(4-O-Me-α-D-GlcAp)]-(1 → 2)-O-β-D-Xylp-(1 → 4)-[O-(4-O-Me-α-D-GlcAp)]-(1 → 2)-O-β-D-Xylp-(1 → 4)-O-β-D-Xylp-(1 → 4)-D-Xyl

7.

Fr. 6-S1: (MeGlcA⁴MeGlcA³Xyl₄), O-(4-O-Me-α-D-GlcAp)-(1 → 2)-O-β-D-Xylp-(1 → 4)-O-[(4-O-Me-α-D-GlcAp)]-(1 → 2)-O-β-D-Xylp-(1 → 4)-O-β-D-Xylp-(1 → 4)-D-Xyl

8.

Fr. 7-S1: (MeGlcA³MeGlc²Xyl₃), O-(4-O-Me-α-D-GlcAp)-(1 → 2)-O-β-D-Xylp-(1 → 4)-O-[(4-O-Me-α-D-GlcAp)]-(1 → 2)-O-β-D-Xylp-(1 → 4)-D-Xyl

Fr. 4-S2 was a new acidic oligosaccharide. The distribution pattern of these vicinal uronic acid units along the D-xylan chain was discussed.     

TfM mutation and masculinization versus feminization of the mouse central nervous system

The sexual behavior of mice of various genotypes has been studied in our stock in which X-linked genes, Tfm and (O^hv), as well as an autosomal dominant gene, Sxr, are maintained. Since the absence of neonatal imprinting in Tfm (O^hv)/Y^ leads to no sexual behavior, we conclude that neonatal imprinting is the prerequisite for feminization as well as masculinization of the central nervous system. Since individual components of sexual behavior may become feminine or absent instead of being masculine in sex-reversed Tfm (O^hv)/+(O⁺, Sxr/+^♂ with mosaic brains, we conclude that neonatal imprinting directly involves individual neurons, and that different degrees of imprinting by the same agent lead to masculinization or feminization. In accordance with recent views, we believe estradiol to be this imprinting agent.We envisage the role of the Tfm locus in the central nervous system as follows: within individual neurons for sexual behavior, the synthesis of aromatizing enzymes is normally inducible by androgens; these enzymes are therefore noninducible in Tfm (O^hv)/Y^. In normal neonates, exposure to testosterone leads to the induced intracellular conversion of testosterone to estradiol, self imprinting by estradiol causing masculinization. Feminization may normally be due to the direct exposure of these neurons to a low circulating concentration of estradiol. An alternative explanation might be that the estradiol-receptor protein in these neurons also is normally inducible by testosterone. In this case, neonatally testosterone-exposed neurons would become inherently more responsive to estradiol than neonatally estradiol-exposed neurons.     

Dietary Regimens Modify Early Onset of Obesity in Mice Haploinsufficient for Rai1

Smith-Magenis syndrome is a complex genomic disorder in which a majority of individuals are obese by adolescence. While an interstitial deletion of chromosome 17p11.2 is the leading cause, mutation or deletion of the RAI1 gene alone results in most features of the disorder. Previous studies have shown that heterozygous knockout of Rai1 results in an obese phenotype in mice and that Smith-Magenis syndrome mouse models have a significantly reduced fecundity and an altered transmission pattern of the mutant Rai1 allele, complicating large, extended studies in these models. In this study, we show that breeding C57Bl/6J Rai1^+/− mice with FVB/NJ to create F1 Rai1^+/− offspring in a mixed genetic background ameliorates both fecundity and Rai1 allele transmission phenotypes. These findings suggest that the mixed background provides a more robust platform for breeding and larger phenotypic studies. We also characterized the effect of dietary intake on Rai1^+/− mouse growth during adolescent and early adulthood developmental stages. Animals fed a high carbohydrate or a high fat diet gained weight at a significantly faster rate than their wild type littermates. Both high fat and high carbohydrate fed Rai1^+/− mice also had an increase in body fat and altered fat distribution patterns. Interestingly, Rai1^+/− mice fed different diets did not display altered fasting blood glucose levels. These results suggest that dietary regimens are extremely important for individuals with Smith- Magenis syndrome and that food high in fat and carbohydrates may exacerbate obesity outcomes.