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Articles 1 - 10 of 10
Full-Text Articles in Life Sciences
Ovarian Development In Mice Requires The Gata4-Fog2 Transcription Complex, Nikolay L. Manuylov, Fatima O. Smagulova, Lyndsay Leach, Sergei G. Tevosian
Ovarian Development In Mice Requires The Gata4-Fog2 Transcription Complex, Nikolay L. Manuylov, Fatima O. Smagulova, Lyndsay Leach, Sergei G. Tevosian
Dartmouth Scholarship
We have demonstrated previously that mammalian sexual differentiation requires both the GATA4 and FOG2 transcriptional regulators to assemble the functioning testis. Here we have determined that the sexual development of female mice is profoundly affected by the loss of GATA4-FOG2 interaction. We have also identified the Dkk1 gene, which encodes a secreted inhibitor of canonical beta-catenin signaling, as a target of GATA4-FOG2 repression in the developing ovary. The tissue-specific ablation of the beta-catenin gene in the gonads disrupts female development. In Gata4(ki/ki); Dkk1(-/-) or Fog2(-/-); Dkk1(-/-) embryos, the normal ovarian gene expression pattern is partially restored. Control of ovarian development …
The Cradle Of The Deltaf508 Mutation, Danish Saleheen, Philippe M Frossard
The Cradle Of The Deltaf508 Mutation, Danish Saleheen, Philippe M Frossard
Department of Biological & Biomedical Sciences
Cystic fibrosis (CF) is the most common autosomal recessive disorder caused due to mutation/s in the CFTR gene. The most common mutation in CFTR worldwide is deltaF508 and cystic fibrosis genetic analysis consortium revealed that this mutation is responsible for approximately 66% of all CF chromosomes in the world. Studies looking at the DNA polymorphic haplotypes created by CF linked markers suggest that deltaF508 has a single origin as this mutation has been found associated exclusively with one marker haplotype. Despite a high prevalence of this mutation in CF patients in northern parts of Europe, findings suggest that this mutation …
Metabolic Engineering Of A Thermophilic Bacterium To Produce Ethanol At High Yield, A. Joe Shaw, Kara K. Podkaminer, Sunil G. Desai, John S. Bardsley, Stephen R. Rogers, Philip G. Thorne, David A. Hogsett, Lee R. Lynd
Metabolic Engineering Of A Thermophilic Bacterium To Produce Ethanol At High Yield, A. Joe Shaw, Kara K. Podkaminer, Sunil G. Desai, John S. Bardsley, Stephen R. Rogers, Philip G. Thorne, David A. Hogsett, Lee R. Lynd
Dartmouth Scholarship
We report engineering Thermoanaerobacterium saccharolyticum, a thermophilic anaerobic bacterium that ferments xylan and biomass-derived sugars, to produce ethanol at high yield. Knockout of genes involved in organic acid formation (acetate kinase, phosphate acetyltransferase, and L-lactate dehydrogenase) resulted in a strain able to produce ethanol as the only detectable organic product and substantial changes in electron flow relative to the wild type. Ethanol formation in the engineered strain (ALK2) utilizes pyruvate:ferredoxin oxidoreductase with electrons transferred from ferredoxin to NAD(P), a pathway different from that in previously described microbes with a homoethanol fermentation. The homoethanologenic phenotype was stable for >150 generations …
Chloroplast Fe(Iii) Chelate Reductase Activity Is Essential For Seedling Viability Under Iron Limiting Conditions, Jeeyon Jeong, Christopher Cohu, Loubna Kerkeb, Marinus Pilon, Erin L. Connolly, Mary Lou Guerinot
Chloroplast Fe(Iii) Chelate Reductase Activity Is Essential For Seedling Viability Under Iron Limiting Conditions, Jeeyon Jeong, Christopher Cohu, Loubna Kerkeb, Marinus Pilon, Erin L. Connolly, Mary Lou Guerinot
Dartmouth Scholarship
Photosynthesis, heme biosynthesis, and Fe-S cluster assembly all take place in the chloroplast, and all require iron. Reduction of iron via a membrane-bound Fe(III) chelate reductase is required before iron transport across membranes in a variety of systems, but to date there has been no definitive genetic proof that chloroplasts have such a reduction system. Here we report that one of the eight members of the Arabidopsis ferric reductase oxidase (FRO) family, FRO7, localizes to the chloroplast. Chloroplasts prepared from fro7 loss-of-function mutants have 75% less Fe(III) chelate reductase activity and contain 33% less iron per microgram of chlorophyll than …
Integration Host Factor Positively Regulates Virulence Gene Expression In Vibrio Cholerae, Emily Stonehouse, Gabriela Kovacikova, Ronald K. Taylor, Karen Skorupski
Integration Host Factor Positively Regulates Virulence Gene Expression In Vibrio Cholerae, Emily Stonehouse, Gabriela Kovacikova, Ronald K. Taylor, Karen Skorupski
Dartmouth Scholarship
Virulence gene expression in Vibrio cholerae is dependent upon a complex transcriptional cascade that is influenced by both specific and global regulators in response to environmental stimuli. Here, we report that the global regulator integration host factor (IHF) positively affects virulence gene expression in V. cholerae. Inactivation of ihfA and ihfB, the genes encoding the IHF subunits, decreased the expression levels of the two main virulence factors tcpA and ctx and prevented toxin-coregulated pilus and cholera toxin production. IHF was found to directly bind to and bend the tcpA promoter region at an IHF consensus site centered at position 162 …
Minimal Components Of The Rna Polymerase Ii Transcription Apparatus Determine The Consensus Tata Box, Gudrun Bjornsdottir, Lawrence C. Myers
Minimal Components Of The Rna Polymerase Ii Transcription Apparatus Determine The Consensus Tata Box, Gudrun Bjornsdottir, Lawrence C. Myers
Dartmouth Scholarship
In Saccharomyces cerevisiae, multiple approaches have arrived at a consensus TATA box sequence of TATA(T/A)A(A/T)(A/G). TATA-binding protein (TBP) affinity alone does not determine TATA box function. To discover how a minimal set of factors required for basal and activated transcription contributed to the sequence requirements for a functional TATA box, we performed transcription reactions using highly purified proteins and CYC1 promoter TATA box mutants. The TATA box consensus sequence is a good predictor of promoter activity. However, several nonconsensus sequences are almost fully functional, indicating that mechanistic requirements are not the only selective pressure on the TATA box. We …
Ponticulin Plays A Role In The Positional Stabilization Of Pseudopods, D. C. Shutt, D. Wessels, K. Wagenknecht, A. Chandrasekhar, Anne L. Hitt, Elizabeth J. Luna, D. R. Soll
Ponticulin Plays A Role In The Positional Stabilization Of Pseudopods, D. C. Shutt, D. Wessels, K. Wagenknecht, A. Chandrasekhar, Anne L. Hitt, Elizabeth J. Luna, D. R. Soll
Elizabeth J. Luna
Ponticulin is a 17-kD glycoprotein that represents a major high affinity link between the plasma membrane and the cortical actin network of Dictyostelium. To assess the role of ponticulin in pseudopod extension and retraction, the motile behavior of two independently generated mutants lacking ponticulin was analyzed using computer-assisted two- and three-dimensional motion analysis systems. More than half of the lateral pseudopods formed off the substratum by ponticulin-minus cells slipped relative to the substratum during extension and retraction. In contrast, all pseudopods formed off the substratum by wild-type cells were positionally fixed in relation to the substratum. Ponticulin-minus cells also formed …
Variation In Molybdenum Content Across Broadly Distributed Populations Of Arabidopsis Thaliana Is Controlled By A Mitochondrial Molybdenum Transporter (Mot1), Ivan Baxter, Balasubramaniam Muthukumar, Hyeong Cheol Park, Peter Buchner, Brett Lahner, John Danku, Keyan Zhao, Joohyun Lee, Malcolm J. Hawkesford, Mary Lou Guerinot, David E. Salt
Variation In Molybdenum Content Across Broadly Distributed Populations Of Arabidopsis Thaliana Is Controlled By A Mitochondrial Molybdenum Transporter (Mot1), Ivan Baxter, Balasubramaniam Muthukumar, Hyeong Cheol Park, Peter Buchner, Brett Lahner, John Danku, Keyan Zhao, Joohyun Lee, Malcolm J. Hawkesford, Mary Lou Guerinot, David E. Salt
Dartmouth Scholarship
Molybdenum (Mo) is an essential micronutrient for plants, serving as a cofactor for enzymes involved in nitrate assimilation, sulfite detoxification, abscisic acid biosynthesis, and purine degradation. Here we show that natural variation in shoot Mo content across 92 Arabidopsis thaliana accessions is controlled by variation in a mitochondrially localized transporter (Molybdenum Transporter 1 - MOT1) that belongs to the sulfate transporter superfamily. A deletion in the MOT1 promoter is strongly associated with low shoot Mo, occurring in seven of the accessions with the lowest shoot content of Mo. Consistent with the low Mo phenotype, MOT1 expression in low Mo accessions …
A Naturally Occurring Mutation In Ropb Suppresses Speb Expression And Reduces M1t1 Group A Streptococcal Systemic Virulence, Andrew Hollands, Ramy K. Aziz, Rita G. Kansal, Malak Kotb, Victor Nizet, Mark J. Walker
A Naturally Occurring Mutation In Ropb Suppresses Speb Expression And Reduces M1t1 Group A Streptococcal Systemic Virulence, Andrew Hollands, Ramy K. Aziz, Rita G. Kansal, Malak Kotb, Victor Nizet, Mark J. Walker
Faculty of Science - Papers (Archive)
Epidemiological studies of group A streptococcus (GAS) have noted an inverse relationship between SpeB expression and invasive disease. However, the role of SpeB in the course of infection is still unclear. In this study we utilize a SpeB-negative M1T1 clinical isolate, 5628, with a naturally occurring mutation in the gene encoding the regulator RopB, to elucidate the role of RopB and SpeB in systemic virulence. Allelic exchange mutagenesis was used to replace the mutated ropB allele in 5628 with the intact allele from the well characterized isolate 5448. The inverse allelic exchange was also performed to replace the intact ropB …
Analysis Of Ki-Ras Exon 2 Gene Mutations In 3-Methylcholanthrene And Butylated Hydroxytoluene-Induced Rat Lung Tissues, Fi̇kri̇ye Polat, Öztürk Özdemi̇r, Şahende Elagöz
Analysis Of Ki-Ras Exon 2 Gene Mutations In 3-Methylcholanthrene And Butylated Hydroxytoluene-Induced Rat Lung Tissues, Fi̇kri̇ye Polat, Öztürk Özdemi̇r, Şahende Elagöz
Turkish Journal of Biology
3-Methylcholanthrene (MCA) is a polycyclic aromatic hydrocarbon and potent carcinogenic agent that is often used in experimental cancer studies. Butylated hydroxytoluene (BHT) has been widely used for many years as an antioxidant to preserve and stabilize the freshness, nutritional value, flavor, and color of foods. The aim of the present study was to investigate the role of the application of MCA and BHT in the development of lung cancer, and to detect any mutation in the Ki-ras gene exon 2. Rats were killed by cervical dislocation 26 weeks after the last BHT injection and lung tissues were surgically removed. Lung …