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https://www.readbyqxmd.com/read/28549169/regulatory-dynamics-of-11p13-suggest-a-role-for-ehf-in-modifying-cf-lung-disease-severity
#1
Lindsay R Stolzenburg, Rui Yang, Jenny L Kerschner, Sara Fossum, Matthew Xu, Andrew Hoffmann, Kay-Marie Lamar, Sujana Ghosh, Sarah Wachtel, Shih-Hsing Leir, Ann Harris
Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene cause cystic fibrosis (CF), but are not good predictors of lung phenotype. Genome-wide association studies (GWAS) previously identified additional genomic sites associated with CF lung disease severity. One of these, at chromosome 11p13, is an intergenic region between Ets homologous factor (EHF) and Apaf-1 interacting protein (APIP). Our goal was to determine the functional significance of this region, which being intergenic is probably regulatory...
May 26, 2017: Nucleic Acids Research
https://www.readbyqxmd.com/read/28548965/inhibition-of-colorectal-cancer-genomic-copy-number-alterations-and-chromosomal-fragile-site-tumor-suppressor-fhit-and-wwox-deletions-by-dna-mismatch-repair
#2
Sohail Jahid, Jian Sun, Ozkan Gelincik, Pedro Blecua, Winfried Edelmann, Raju Kucherlapati, Kathy Zhou, Maria Jasin, Zeynep H Gümüş, Steven M Lipkin
Homologous recombination (HR) enables precise DNA repair after DNA double strand breaks (DSBs) using identical sequence templates, whereas homeologous recombination (HeR) uses only partially homologous sequences. Homeologous recombination introduces mutations through gene conversion and genomic deletions through single-strand annealing (SSA). DNA mismatch repair (MMR) inhibits HeR, but the roles of mammalian MMR MutL homologues (MLH1, PMS2 and MLH3) proteins in HeR suppression are poorly characterized. Here, we demonstrate that mouse embryonic fibroblasts (MEFs) carrying Mlh1, Pms2, and Mlh3 mutations have higher HeR rates, by using 7,863 uniquely mapping paired direct repeat sequences (DRs) in the mouse genome as endogenous gene conversion and SSA reporters...
May 10, 2017: Oncotarget
https://www.readbyqxmd.com/read/28546828/improving-the-thermostability-of-a-fungal-gh11-xylanase-via-site-directed-mutagenesis-guided-by-sequence-and-structural-analysis
#3
Nanyu Han, Huabiao Miao, Junmei Ding, Junjun Li, Yuelin Mu, Junpei Zhou, Zunxi Huang
BACKGROUND: Xylanases have been widely employed in many industrial processes, and thermophilic xylanases are in great demand for meeting the high-temperature requirements of biotechnological treatments. In this work, we aim to improve the thermostability of XynCDBFV, a glycoside hydrolase (GH) family 11 xylanase from the ruminal fungus Neocallimastix patriciarum, by site-directed mutagenesis. We report favorable mutations at the C-terminus from B-factor comparison and multiple sequence alignment...
2017: Biotechnology for Biofuels
https://www.readbyqxmd.com/read/28546558/probing-the-roles-of-calcium-binding-sites-during-the-folding-of-human-peptidylarginine-deiminase-4
#4
Yi-Liang Liu, Chien-Yun Lee, Yu-Ni Huang, Hui-Yi Chen, Guang-Yaw Liu, Hui-Chih Hung
Our recent studies of peptidylarginine deiminase 4 (PAD4) demonstrate that its non-catalytic Ca(2+)-binding sites play a crucial role in the assembly of the correct geometry of the enzyme. Here, we examined the folding mechanism of PAD4 and the role of Ca(2+) ions in the folding pathway. Multiple mutations were introduced into the calcium-binding sites, and these mutants were termed the Ca1_site, Ca2_site, Ca3_site, Ca4_site and Ca5_site mutants. Our data indicate that during the unfolding process, the PAD4 dimer first dissociates into monomers, and the monomers then undergo a three-state denaturation process via an intermediate state formation...
May 25, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28545018/fixed-differences-in-the-3-utr-of-buffalo-prnp-gene-provide-binding-sites-for-mirnas-post-transcriptional-regulation
#5
Hui Zhao, Siqi Wang, Lixia Guo, Yanli Du, Linlin Liu, Tengfei Ma, Newton O Otecko, Canpeng Li, Yaping Zhang
Bovine spongiform encephalopathy, a member of transmissible spongiform encephalopathies, has not been reported in buffaloes, Bubalus bubalis. Prion protein (PrP), encoded by the prion protein gene (PRNP), is fundamental in the pathogenesis of transmissible spongiform encephalopathies. We previously showed that buffaloes express more PrP proteins but lower PRNP mRNA than cattle in several pivotal tissues like the obex. Therefore, we sought to establish whether genetic variability in PRNP 3'UTR, mediated by miRNA down-regulation, causes PrP expression differences between cattle and buffaloes...
May 2, 2017: Oncotarget
https://www.readbyqxmd.com/read/28544059/objective-assessment-of-the-evolutionary-action-equation-for-the-fitness-effect-of-missense-mutations-across-cagi-blinded-contests
#6
Panagiotis Katsonis, Olivier Lichtarge
A major challenge in genome interpretation is to estimate the fitness effect of coding variants of unknown significance (VUS). Labor, limited understanding of protein functions, and lack of assays generally limit direct experimental assessment of VUS, and make robust and accurate computational approaches a necessity. Often, however, algorithms that predict mutational effect disagree amongst themselves and with experimental data, slowing their adoption for clinical diagnostics. To objectively assess such methods, the Critical Assessment of Genome Interpretation (CAGI) community organizes contests to predict unpublished experimental data, available only to CAGI assessors...
May 23, 2017: Human Mutation
https://www.readbyqxmd.com/read/28540701/inverse-pcr-for-point-mutation-introduction
#7
Diogo Silva, Gustavo Santos, Mário Barroca, Tony Collins
Inverse PCR is a powerful tool for the rapid introduction of desired mutations at desired positions in a circular double-stranded DNA sequence. Here, custom-designed mutant primers oriented in the inverse direction are used to amplify the entire circular template with incorporation of the required mutation(s). By careful primer design it can be used to perform such diverse modifications as the introduction of point mutations and multiple mutations, the insertion of new sequences, and even sequence deletions...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28540421/yeast-env9-encodes-a-conserved-lipid-droplet-ld-short-chain-dehydrogenase-involved-in-ld-morphology
#8
Ikha M Siddiqah, Surya P Manandhar, Stephanie M Cocca, Teli Hsueh, Vanessa Cervantes, Editte Gharakhanian
Lipid droplets (LDs) have emerged as dynamic and interactive organelles with important roles in lipid metabolism and membrane biogenesis. Here, we report that Saccharomyces cerevisiae Env9 is a novel conserved oxidoreductase involved in LD morphology. Microscopic and biochemical studies confirm localization of tagged Env9 to LDs and implicate its C-terminal hydrophobic domain (aa241-265) in its membrane association and stability. Confocal studies reveal a role for Env9 in LD morphology. Env9 positively affects both formation of large LDs upon overexpression and LD proliferation under poor carbon source...
May 24, 2017: Current Genetics
https://www.readbyqxmd.com/read/28538097/biochemical-characterization-of-the-functional-roles-of-residues-in-the-active-site-of-the-%C3%AE-galactosidase-from-bacillus-circulans-atcc-31382
#9
Huifang Yin, Tjaard Pijning, Xiangfeng Meng, Lubbert Dijkhuizen, Sander Sebastiaan van Leeuwen
The β-galactosidase enzyme from Bacillus circulans ATCC 31382 BgaD is widely used in the food industry to produce prebiotic galactooligosaccharides (GOS). Recently, the crystal structure of a C-terminally truncated version of the enzyme (BgaD-D) has been elucidated. The roles of active site amino acid residues in β-galactosidase enzyme reaction and product specificity have remained unknown. Based on a structural alignment of the β-galactosidase enzymes BgaD-D from Bacillus circulans and BgaA from Streptococcus pneumoniae, and the complex of BgaA with LacNAc, we identified 8 active site amino acid residues (Arg185, Asp481, Lys487, Tyr511, Trp570, Trp593, Glu601, and Phe616) in BgaD-D...
May 24, 2017: Biochemistry
https://www.readbyqxmd.com/read/28535298/ledipasvir-sofosbuvir-plus-ribavirin-in-treatment-naive-patients-with-hepatitis-c-virus-genotype-3-infection-an-open-label-study
#10
Jordan J Feld, Alnoor Ramji, Stephen D Shafran, Bernard Willems, Paul Marotta, Emmanuelle Huchet, Marie-Louise Vachon, Evguenia S Svarovskaia, K C Huang, Robert H Hyland, Chohee Yun, Benedetta Massetto, Diana M Brainard, John G McHutchison, Edward Tam, Robert Bailey, Curtis Cooper, Eric M Yoshida, Susan Greenbloom, Magdy Elkhashab, Sergio Borgia, Mark G Swain
Background.: Patients chronically infected with genotype 3 hepatitis C virus (HCV) have faster disease progression and are less responsive to current direct-acting antiviral regimens than patients infected with other genotypes. We conducted an open-label trial to evaluate the safety, tolerability, and efficacy of ledipasvir and sofosbuvir plus ribavirin in patients with genotype 3 HCV infection. Methods.: We enrolled treatment-naive patients with and without compensated cirrhosis at 15 sites in Canada...
May 23, 2017: Clinical Infectious Diseases: An Official Publication of the Infectious Diseases Society of America
https://www.readbyqxmd.com/read/28534256/crispr-cas9-mediated-correction-of-human-genetic-disease
#11
REVIEW
Ke Men, Xingmei Duan, Zhiyao He, Yang Yang, Shaohua Yao, Yuquan Wei
The clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) protein 9 system (CRISPR/Cas9) provides a powerful tool for targeted genetic editing. Directed by programmable sequence-specific RNAs, this system introduces cleavage and double-stranded breaks at target sites precisely. Compared to previously developed targeted nucleases, the CRISPR/Cas9 system demonstrates several promising advantages, including simplicity, high specificity, and efficiency. Several broad genome-editing studies with the CRISPR/Cas9 system in different species in vivo and ex vivo have indicated its strong potential, raising hopes for therapeutic genome editing in clinical settings...
May 3, 2017: Science China. Life Sciences
https://www.readbyqxmd.com/read/28533784/the-divergence-of-flowering-time-modulated-by-ft-tfl1-is-independent-to-their-interaction-and-binding-activities
#12
Zhen Wang, Ruiguang Yang, Upendra K Devisetty, Julin N Maloof, Yang Zuo, Jingjing Li, Yuxiao Shen, Jian Zhao, Manzhu Bao, Guogui Ning
FLOWERING LOCUS T (FT) and TERMINAL FLOWER1 (TFL1) proteins share highly conserved amino acid residues but they play opposite regulatory roles in promoting and repressing the flowering response, respectively. Previous substitution models and functional analysis have identified several key amino acid residues which are critical for the promotion of flowering. However, the precise relationship between naturally occurring FT/TFL1 homologs and the mechanism of their role in flowering is still unclear. In this study, FT/TFL1 homologs from eight Rosaceae species, namely, Spiraea cantoniensis, Pyracantha fortuneana, Photinia serrulata, Fragaria ananassa, Rosa hybrida, Prunus mume, Prunus persica and Prunus yedoensis, were isolated...
2017: Frontiers in Plant Science
https://www.readbyqxmd.com/read/28531234/directed-evolution-to-improve-the-catalytic-efficiency-of-urate-oxidase-from-bacillus-subtilis
#13
Wenjie Li, Shouteng Xu, Biao Zhang, Yelin Zhu, Yan Hua, Xin Kong, Lianhong Sun, Jiong Hong
Urate oxidase is a key enzyme in purine metabolism and catalyzes the oxidation of uric acid to allantoin. It is used to treat hyperuricemia and gout, and also in a diagnostic kit. In this study, error-prone polymerase chain reaction and staggered extension process was used to generate a mutant urate oxidase with improved enzyme activity from Bacillus subtilis. After several rounds of mutagenesis and screening, two mutants 6E9 and 8E279 were obtained which exhibited 2.99 and 3.43 times higher catalytic efficiency, respectively...
2017: PloS One
https://www.readbyqxmd.com/read/28531214/suspected-lynch-syndrome-associated-msh6-variants-a-functional-assay-to-determine-their-pathogenicity
#14
Hellen Houlleberghs, Anne Goverde, Jarnick Lusseveld, Marleen Dekker, Marco J Bruno, Fred H Menko, Arjen R Mensenkamp, Manon C W Spaander, Anja Wagner, Robert M W Hofstra, Hein Te Riele
Lynch syndrome (LS) is a hereditary cancer predisposition caused by inactivating mutations in DNA mismatch repair (MMR) genes. Mutations in the MSH6 DNA MMR gene account for approximately 18% of LS cases. Many LS-associated sequence variants are nonsense and frameshift mutations that clearly abrogate MMR activity. However, missense mutations whose functional implications are unclear are also frequently seen in suspected-LS patients. To conclusively diagnose LS and enroll patients in appropriate surveillance programs to reduce morbidity as well as mortality, the functional consequences of these variants of uncertain clinical significance (VUS) must be defined...
May 22, 2017: PLoS Genetics
https://www.readbyqxmd.com/read/28529507/a-novel-and-efficient-method-for-bacteria-genome-editing-employing-both-crispr-cas9-and-an-antibiotic-resistance-cassette
#15
Hong Zhang, Qiu-Xiang Cheng, Ai-Min Liu, Guo-Ping Zhao, Jin Wang
As Cas9-mediated cleavage requires both protospacer and protospacer adjacent motif (PAM) sequences, it is impossible to employ the CRISPR/Cas9 system to directly edit genomic sites without available PAM sequences nearby. Here, we optimized the CRISPR/Cas9 system and developed an innovative two-step strategy for efficient genome editing of any sites, which did not rely on the availability of PAM sequences. An antibiotic resistance cassette was employed as both a positive and a negative selection marker. By integrating the optimized two-plasmid CRISPR/Cas system and donor DNA, we achieved gene insertion and point mutation with high efficiency in Escherichia coli, and importantly, obtained clean mutants with no other unwanted mutations...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28527569/estrogen-hormone-biology
#16
Katherine J Hamilton, Sylvia C Hewitt, Yukitomo Arao, Kenneth S Korach
The hormone estrogen is involved in both female and male reproduction, as well as numerous other biological systems including the neuroendocrine, vascular, skeletal, and immune systems. Therefore, it is also implicated in many different diseases and conditions such as infertility, obesity, osteoporosis, endometriosis, and a variety of cancers. Estrogen works through its two distinct nuclear receptors, estrogen receptor alpha (ERα) and estrogen receptor beta (ERβ). Various transcriptional regulation mechanisms have been identified as the mode of action for estrogen, mainly the classical mechanism with direct DNA binding but also a nongenomic mode of action and one using tethered or indirect binding...
2017: Current Topics in Developmental Biology
https://www.readbyqxmd.com/read/28527335/dissection-of-cis-regulatory-element-architecture-of-the-rice-oleosin-gene-promoters-to-assess-abscisic-acid-responsiveness-in-suspension-cultured-rice-cells
#17
Sol Kim, Soo-Bin Lee, Chae-Seong Han, Mi-Na Lim, Sung-Eun Lee, In Sun Yoon, Yong-Sic Hwang
Oleosins are the most abundant proteins in the monolipid layer surrounding neutral storage lipids that form oil bodies in plants. Several lines of evidence indicate that they are physiologically important for the maintenance of oil body structure and for mobilization of the lipids stored inside. Rice has six oleosin genes in its genome, the expression of all of which was found to be responsive to abscisic acid (ABA) in our examination of mature embryo and aleurone tissues. The 5'-flanking region of OsOle5 was initially characterized for its responsiveness to ABA through a transient expression assay system using the protoplasts from suspension-cultured rice cells...
May 1, 2017: Journal of Plant Physiology
https://www.readbyqxmd.com/read/28527117/non-viral-and-viral-delivery-systems-for-crispr-cas9-technology-in-the-biomedical-field
#18
REVIEW
Zhi-Yao He, Ke Men, Zhou Qin, Yang Yang, Ting Xu, Yu-Quan Wei
The clustered regularly interspaced short palindromic repeats (CRISPR)-associated protein 9 (CRISPR-Cas9) system provides a novel genome editing technology that can precisely target a genomic site to disrupt or repair a specific gene. Some CRISPR-Cas9 systems from different bacteria or artificial variants have been discovered or constructed by biologists, and Cas9 nucleases and single guide RNAs (sgRNA) are the major components of the CRISPR-Cas9 system. These Cas9 systems have been extensively applied for identifying therapeutic targets, identifying gene functions, generating animal models, and developing gene therapies...
May 2, 2017: Science China. Life Sciences
https://www.readbyqxmd.com/read/28526714/constans-imparts-dna-sequence-specificity-to-the-histone-fold-nf-yb-nf-yc-dimer
#19
Nerina Gnesutta, Roderick W Kumimoto, Swadhin Swain, Matteo Chiara, Chamindika Siriwardana, David Stephen Horner, Ben F Holt, Roberto Mantovani
NF-Y is a heterotrimeric transcription factor that binds CCAAT elements. The NF-Y trimer is composed of a Histone Fold Domain (HFD) dimer (NF-YB/NF-YC) and NF-YA, which confers DNA sequence-specificity. NF-YA shares a conserved domain with the CCT (CONSTANS, CONSTANS-LIKE, TOC1) proteins. We show that CONSTANS (CO/BBX1), a master flowering regulator, forms a trimer with Arabidopsis NF-YB2/NF-YC3 to efficiently bind the CORE element of the FT promoter. We term this complex NF-CO. Using saturation mutagenesis EMSAs and RNA-Seq profiling of co, nf-yb, and nf-yc mutants, we identify CCACA elements as the core NF-CO binding site...
May 19, 2017: Plant Cell
https://www.readbyqxmd.com/read/28522865/lipoxygenase-2-from-cyanothece-sp-controls-dioxygen-insertion-by-steric-shielding-and-substrate-fixation
#20
Julia Newie, Piotr Neumann, Martin Werner, Ricardo A Mata, Ralf Ficner, Ivo Feussner
The biological function of lipoxygenases depends on the regio and stereo specific formation of fatty acid-derived hydroperoxides and different concepts exist to explain the mechanism that directs dioxygen to a specific carbon atom within the substrate. Here, we report the 1.8 Å resolution crystal structure of a cyanobacterial lipoxygenase that produces bis-allylic hydroperoxides (CspLOX2). Site directed mutagenesis experiments combined with computational approaches reveal that residues around the active site direct dioxygen to a preferred carbon atom and stereo configuration in the substrate fatty acid...
May 18, 2017: Scientific Reports
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