1. |
- Bethke, Lara, et al.
(författare)
-
CASP8 D302H and meningioma risk : an analysis of five case-control series
- 2009
-
Ingår i: Cancer Letters. - Clare : Elsevier. - 0304-3835 .- 1872-7980. ; 273:2, s. 312-315
-
Tidskriftsartikel (refereegranskat)abstract
- Caspase 8 (CASP8) is a key regulator of apoptosis or programmed cell death, and hence a defence against cancer. The CASP8 polymorphism D302H has recently been shown to influence the risk of breast cancer. We tested the hypothesis that the CASP8 polymorphism D302H may influence risk of meningioma through analysis of five independent series of case patients and controls (n=631 and 637, respectively). Carrier status for 302H was not associated with a statistically significantly increased risk (OR=1.16; 95% CI: 0.87-1.53; P=0.31) making it unlikely that this variant contributes to the inherited risk of meningioma.
|
|
2. |
- Bethke, Lara, et al.
(författare)
-
Comprehensive analysis of DNA repair gene variants and risk of meningioma
- 2008
-
Ingår i: Journal of the National Cancer Institute. - : Oxford University Press. - 0027-8874 .- 1460-2105. ; 100:4, s. 270-276
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Meningiomas account for up to 37% of all primary brain tumors. Genetic susceptibility to meningioma is well established, with the risk among relatives of meningioma patients being approximately threefold higher than that in the general population. A relationship between risk of meningioma and exposure to ionizing radiation is also well known and led us to examine whether variants in DNA repair genes contribute to disease susceptibility.Methods: We analyzed 1127 tagging single-nucleotide polymorphisms (SNPs) that were selected to capture most of the common variation in 136 DNA repair genes in five case–control series (631 case patients and 637 control subjects) from four countries in Europe. We also analyzed 388 putative functional SNPs in these genes for their association with meningioma. All statistical tests were two-sided.Results: The SNP rs4968451, which maps to intron 4 of the gene that encodes breast cancer susceptibility gene 1–interacting protein 1, was consistently associated with an increased risk of developing meningioma. Across the five studies, the association was highly statistically significant (trend odds ratio = 1.57, 95% confidence interval = 1.28 to 1.93; Ptrend = 8.95 × 10−6; P = .009 after adjusting for multiple testing).Conclusions: We have identified a novel association between rs4968451 and meningioma risk. Because approximately 28% of the European population are carriers of at-risk genotypes for rs4968451, the variant is likely to make a substantial contribution to the development of meningioma.
|
|
3. |
- Bethke, Lara, et al.
(författare)
-
Comprehensive analysis of the role of DNA repair gene polymorphisms on risk of glioma
- 2008
-
Ingår i: Human Molecular Genetics. - : Oxford University Press. - 0964-6906 .- 1460-2083. ; 17:6, s. 800-805
-
Tidskriftsartikel (refereegranskat)abstract
- Much of the variation in inherited risk of glioma is likely to be explained by combinations of common low risk variants. The established relationship between glioma risk and exposure to ionizing radiation led us to examine whether variants in the DNA repair genes contribute to disease susceptibility. We evaluated 1127 haplotype-tagging single-nucleotide polymorphisms (SNPs) supplemented with 388 putative functional SNPs to capture most of the common variation in 136 DNA repair genes, in five unique case–control series from four different countries (1013 cases, 1016 controls). We identified 16 SNPs associated with glioma risk at the 1% significance level. The highest association observed across the five independent case–control datasets involved rs243356, which maps to intron 3 of CHAF1A (trend odds ratio, 1.32; 95% confidence interval 1.14–1.54; P = 0.0002; false-positive report probability = 0.055, based on a prior probability of 0.01). Our results provide additional support for the hypothesis that low penetrance variants contribute to the risk of developing glioma and suggest that a genetic variant located in or around the CHAF1A gene contributes to disease risk.
|
|
4. |
- Bethke, Lara, et al.
(författare)
-
Functional polymorphisms in folate metabolism genes influence the risk of meningioma and glioma
- 2008
-
Ingår i: Cancer Epidemiology, Biomarkers and Prevention. - : American Association for Cancer Research (AACR). - 1055-9965 .- 1538-7755. ; 17:5, s. 1195-1202
-
Tidskriftsartikel (refereegranskat)abstract
- Folate metabolism plays an important role in carcinogenesis. To test the hypothesis that polymorphic variation in the folate metabolism genes 5,10-methylenetetrahydrofolate reductase (MTHFR), methionine synthase (MTRR), and methionine synthase reductase (MTR) influences the risk of primary brain tumors, we genotyped 1,005 glioma cases, 631 meningioma cases, and 1,101 controls for the MTHFR C677A and A1298C, MTRR A66G, and MTR A2756G variants. MTHFR C677T-A1298C diplotypes were associated with risk of meningioma (P = 0.002) and glioma (P = 0.02); risks were increased with genotypes associated with reduced MTHFR activity. The highest risk of meningioma was associated with heterozygosity for both MTHFR variants [odds ratio (OR), 2.11; 95% confidence interval (95% CI), 1.42-3.12]. The corresponding OR for glioma was 1.23 (95% CI, 0.91-1.66). A significant association between risk of meningioma and homozygosity for MTRR 66G was also observed (OR, 1.41; 95% CI, 1.02-1.94). Our findings provide support for the role of folate metabolism in the development of primary brain tumors. In particular, genotypes associated with increased 5,10-methylenetetrahydrofolate levels are associated with elevated risk.
|
|
5. |
- Bethke, Lara, et al.
(författare)
-
The Common D302H Variant of CASP8 Is Associated with Risk of Glioma
- 2008
-
Ingår i: Cancer Epidemiology, Biomarkers and Prevention. - : American Association for Cancer Research (AACR). - 1055-9965 .- 1538-7755. ; 17:4, s. 987-989
-
Tidskriftsartikel (refereegranskat)abstract
- Caspase 8 (CASP8) is a key regulator of apoptosis or programmed cell death, and, hence, a defense against cancer. We tested the hypothesis that the CASP8 polymorphism D302H influences risk of glioma through analysis of five series of glioma case patients and controls (n = 1,005 and 1,011, respectively). Carrier status for the rare allele of D302H was associated with a 1.37-fold increased risk (95% confidence interval, 1.10-1.70; P = 0.004). The association of CASP8 D302H with glioma risk indicates the importance of inherited variation in the apoptosis pathway in susceptibility to this form of primary brain tumor.
|
|
6. |
- Blikstad, Cecilia, et al.
(författare)
-
Stereoselective oxidation of aryl-substituted vicinal diols into chiral α-hydroxy aldehydes by re-engineered propanediol oxidoreductase
- 2013
-
Ingår i: ACS Catalysis. - : American Chemical Society (ACS). - 2155-5435. ; 3:12, s. 3016-3025
-
Tidskriftsartikel (refereegranskat)abstract
- α-Hydroxy aldehydes are chiral building blocks used in synthesis of natural products and synthetic drugs. One route to their production is by regioselective oxidation of vicinal diols and, in this work, we aimed to perform the oxidation of 3-phenyl-1,2-propanediol into the corresponding α‑hydroxy aldehyde applying enzyme catalysis. Propanediol oxidoreductase from E. coli efficiently catalyzes the stereoselective oxidation of S-1,2-propanediol into S-lactaldehyde. The enzyme, however, shows no detectable activity with aryl-substituted or other bulky alcohols. We conducted ISM-driven directed evolution on FucO and were able to isolate several mutants that were active with S-3-phenyl-1,2-propanediol. The most efficient variant displayed a kcat/KM of 40 s-1M-1 and the most enantioselective variant an E-value (S/R) of 80. Furthermore, other isolated variants showed up to 4400-fold increased activity with another bulky substrate, phenylacetaldehyde. The results with engineered propanediol oxidoreductases identified amino acids important for substrate selectivity and asymmetric synthesis of aryl-substituted α-hydroxy aldehydes. In conclusion, our study demonstrates the feasibility of tailoring the catalytic properties of propanediol oxidoreductase for biocatalytic properties.
|
|
7. |
- Blikstad, Cecilia, et al.
(författare)
-
Substrate scope and selectivity in offspring to an enzyme subjected to directed evolution
- 2014
-
Ingår i: The FEBS Journal. - : Wiley. - 1742-464X .- 1742-4658. ; 281:10, s. 2387-2398
-
Tidskriftsartikel (refereegranskat)abstract
- We have analyzed the effects of mutations inserted during directed evolution of a specialized enzyme, Escherichia coli S-1,2-propanediol oxidoreductase (FucO). The kinetic properties of evolved variants have been determined and the observed differences have been rationalized by modeling the tertiary structures of isolated variants and the wild-type enzyme. The native substrate, S-1,2-propanediol, as well as phenylacetaldehyde and 2S-3-phenylpropane-1,2-diol, which are new substrates accepted by isolated variants, were docked into the active sites. The study provides a comprehensive picture of how acquired catalytic properties have arisen via an intermediate generalist enzyme, which had acquired a single mutation (L259V) in the active site. Further mutagenesis of this generalist resulted in a new specialist catalyst. We have also been able to relate the native enzyme activities to the evolved ones and linked the differences to individual amino acid residues important for activity and selectivity. F254 plays a dual role in the enzyme function. First, mutation of F254 into an isoleucine weakens the interactions with the coenzyme thereby increasing its dissociation rate from the active site and resulting in a four-fold increase in turnover number with S-1,2-propanediol. Second, F254 is directly involved in binding of aryl-substituted substrates via π–π interactions. On the other hand, N151 is critical in determining the substrate scope since the side chain amide group stabilizes binding of 1,2-substituted diols and is apparently necessary for enzymatic activity with these substrates. Moreover, the side chain of N151 introduces steric hindrance, which prevents high activity with phenylacetaldehyde. Additionally, the hydroxyl group of T149 is required to maintain the catalytically important hydrogen bonding network.
|
|
8. |
|
|
9. |
- Edqvist, Johan, et al.
(författare)
-
Plant lipid transfer proteins: are we finally closing in on the roles of these enigmatic proteins?
- 2018
-
Ingår i: Journal of Lipid Research. - : AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC. - 0022-2275 .- 1539-7262. ; 59:8, s. 1374-1382
-
Forskningsöversikt (refereegranskat)abstract
- The nonspecific lipid transfer proteins (LTPs) are small compact proteins folded around a tunnel-like hydrophobic cavity, making them suitable for lipid binding and transport. LTPs are encoded by large gene families in all land plants, but they have not been identified in algae or any other organisms. Thus, LTPs are considered key proteins for plant survival on and colonization of land. LTPs are abundantly expressed in most plant tissues, both above and below ground. They are usually localized to extracellular spaces outside the plasma membrane. Although the in vivo functions of LTPs remain unclear, accumulating evidence suggests a role for LTPs in the transfer and deposition of monomers required for assembly of the waterproof lipid barriers, such as cutin and cuticular wax, suberin, and sporopollenin, formed on many plant surfaces. Some LTPs may be involved in other processes, such as signaling during pathogen attacks. Here, we present the current status of LTP research with a focus on the role of these proteins in lipid barrier deposition and cell expansion. We suggest that LTPs facilitate extracellular transfer of barrier materials and adhesion between barriers and extracellular materials. A growing body of research may uncover the true role of LTPs in plants.
|
|
10. |
- Edqvist, Johan, et al.
(författare)
-
Plants express a lipid transfer protein with high similarity to mammalian sterol carrier protein-2.
- 2004
-
Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 279:51, s. 53544-53
-
Tidskriftsartikel (refereegranskat)abstract
- This is the first report describing the cloning and characterization of sterol carrier protein-2 (SCP-2) from plants. Arabidopsis thaliana SCP-2 (AtSCP-2) consists of 123 amino acids with a molecular mass of 13.6 kDa. AtSCP-2 shows 35% identity and 56% similarity to the human SCP-2-like domain present in the human D-bifunctional protein (DBP) and 30% identity and 54% similarity to the human SCP-2 encoded by SCP-X. The presented structural models of apo-AtSCP-2 and the ligand-bound conformation of AtSCP-2 reveal remarkable similarity with two of the structurally known SCP-2s, the SCP-2-like domain of human DBP and the rabbit SCP-2, correspondingly. The AtSCP-2 models in both forms have a similar hydrophobic ligand-binding tunnel, which is extremely suitable for lipid binding. AtSCP-2 showed in vitro transfer activity of BODIPY-phosphatidylcholine (BODIPY-PC) from donor membranes to acceptor membranes. The transfer of BODIPY-PC was almost completely inhibited after addition of 1-palmitoyl 2-oleoyl phosphatidylcholine or ergosterol. Dimyristoyl phosphatidic acid, stigmasterol, steryl glucoside, and cholesterol showed a moderate to marginal ability to lower the BODIPY-PC transfer rate, and the single chain palmitic acid and stearoyl-coenzyme A did not affect transfer at all. Expression analysis showed that AtSCP-2 mRNA is accumulating in most plant tissues. Plasmids carrying fusion genes between green fluorescent protein and AtSCP-2 were transformed with particle bombardment to onion epidermal cells. The results from analyzing the transformants indicate that AtSCP-2 is localized to peroxisomes.
|
|