Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 14 of 14
Full-Text Articles in Life Sciences
Alternative Use Of Dna Binding Domains By The Neurospora White Collar Complex Dictates Circadian Regulation And Light Responses, Bin Wang, Xiaoying Zhou, Jennifer J. Loros, Jay C. Dunlap
Alternative Use Of Dna Binding Domains By The Neurospora White Collar Complex Dictates Circadian Regulation And Light Responses, Bin Wang, Xiaoying Zhou, Jennifer J. Loros, Jay C. Dunlap
Dartmouth Scholarship
In the Neurospora circadian system, the White Collar complex (WCC) of WC-1 and WC-2 drives transcription of the circadian pacemaker gene frequency (frq), whose gene product, FRQ, as a part of the FRQ-FRH complex (FFC), inhibits its own expression. The WCC is also the principal Neurospora photoreceptor; WCC-mediated light induction of frq resets the clock, and all acute light induction is triggered by WCC binding to promoters of light-induced genes. However, not all acutely light-induced genes are also clock regulated, and conversely, not all clock-regulated direct targets of WCC are light induced; the structural determinants governing the shift …
Period-1 Encodes An Atp-Dependent Rna Helicase That Influences Nutritional Compensation Of The Neurospora Circadian Clock, Jillian M. Emerson, Bradley M. Bartholomai, Carol S. Ringelberg, Scott E. Baker, Jennifer Loros, Jay Dunlap
Period-1 Encodes An Atp-Dependent Rna Helicase That Influences Nutritional Compensation Of The Neurospora Circadian Clock, Jillian M. Emerson, Bradley M. Bartholomai, Carol S. Ringelberg, Scott E. Baker, Jennifer Loros, Jay Dunlap
Dartmouth Scholarship
Mutants in the period-1 (prd-1) gene, characterized by a recessive allele, display a reduced growth rate and period lengthening of the developmental cycle controlled by the circadian clock. We refined the genetic location of prd-1 and used whole genome sequencing to find the mutation defining it, confirming the identity of prd-1 by rescuing the mutant circadian phenotype via transformation. PRD-1 is an RNA helicase whose orthologs, DDX5 [DEAD (Asp-Glu-Ala-Asp) Box Helicase 5] and DDX17 in humans and DBP2 (Dead Box Protein 2) in yeast, are implicated in various processes, including transcriptional regulation, elongation, and termination, ribosome biogenesis, and mRNA decay. …
Excision Dynamics Of Vibrio Pathogenicity Island-2 From Vibrio Cholerae: Role Of A Recombination Directionality Factor Vefa, Salvador Almagro-Moreno, Michael G. Napolitano, E. Fidelma Boyd
Excision Dynamics Of Vibrio Pathogenicity Island-2 From Vibrio Cholerae: Role Of A Recombination Directionality Factor Vefa, Salvador Almagro-Moreno, Michael G. Napolitano, E. Fidelma Boyd
Dartmouth Scholarship
Vibrio Pathogenicity Island-2 (VPI-2) is a 57 kb region present in choleragenic V. cholerae isolates that is required for growth on sialic acid as a sole carbon source. V. cholerae non-O1/O139 pathogenic strains also contain VPI-2, which in addition to sialic acid catabolism genes also encodes a type 3 secretion system in these strains. VPI-2 integrates into chromosome 1 at a tRNA-serine site and encodes an integrase intV2 (VC1758) that belongs to the tyrosine recombinase family. ntV2 is required for VPI-2 excision from chromosome 1, which occurs at very low levels, and formation of a non-replicative circular intermediate.
Genetic And Molecular Characterization Of A Cryptochrome From The Filamentous Fungus Neurospora Crassa, Allan C. Froehlich, Chen-Hui Chen, William J. Belden, Cornelia Madeti
Genetic And Molecular Characterization Of A Cryptochrome From The Filamentous Fungus Neurospora Crassa, Allan C. Froehlich, Chen-Hui Chen, William J. Belden, Cornelia Madeti
Dartmouth Scholarship
In plants and animals, cryptochromes function as either photoreceptors or circadian clock components. We have examined the cryptochrome from the filamentous fungus Neurospora crassa and demonstrate that Neurospora cry encodes a DASH-type cryptochrome that appears capable of binding flavin adenine dinucleotide (FAD) and methenyltetrahydrofolate (MTHF). The cry transcript and CRY protein levels are strongly induced by blue light in a wc-1-dependent manner, and cry transcript is circadianly regulated, with a peak abundance opposite in phase to frq. Neither deletion nor overexpression of cry appears to perturb the free-running circadian clock. However, cry disruption knockout mutants show a small phase delay …
The Yeast Orthologue Of Grasp65 Forms A Complex With A Coiled-Coil Protein That Contributes To Er To Golgi Traffic, Rudy Behnia, Francis A. Barr, John J. Flanagan, Charles Barlowe, Sean Munro
The Yeast Orthologue Of Grasp65 Forms A Complex With A Coiled-Coil Protein That Contributes To Er To Golgi Traffic, Rudy Behnia, Francis A. Barr, John J. Flanagan, Charles Barlowe, Sean Munro
Dartmouth Scholarship
The mammalian Golgi protein GRASP65 is required in assays that reconstitute cisternal stacking and vesicle tethering. Attached to membranes by an N-terminal myristoyl group, it recruits the coiled-coil protein GM130. The relevance of this system to budding yeasts has been unclear, as they lack an obvious orthologue of GM130, and their only GRASP65 relative (Grh1) lacks a myristoylation site and has even been suggested to act in a mitotic checkpoint. In this study, we show that Grh1 has an N-terminal amphipathic helix that is N-terminally acetylated and mediates association with the cis-Golgi. We find that Grh1 forms a complex with …
Phylogenetic Analysis Of The Formin Homology 2 Domain, Henry N. Higgs, Kevin J. Peterson
Phylogenetic Analysis Of The Formin Homology 2 Domain, Henry N. Higgs, Kevin J. Peterson
Dartmouth Scholarship
Formin proteins are key regulators of eukaryotic actin filament assembly and elongation, and many species possess multiple formin isoforms. A nomenclature system based on fundamental features would be desirable, to aid the rapid identification and characterization of novel formins. In this article, we attempt to systematize the formin family by performing phylogenetic analyses of the formin homology 2 (FH2) domain, an independently folding region common to all formins, which alone can influence actin dynamics. Through database searches, we identify 101 FH2 domains from 26 eukaryotic species, including 15 in mice. Sequence alignments reveal a highly conserved yeast-specific insert in the …
The C. Elegans Heterochronic Gene Lin-46 Affects Developmental Timing At Two Larval Stages And Encodes A Relative Of The Scaffolding Protein Gephyrin, A. S.-R. Pepper, Jill E. Mccane, Kevin Kemper, Dennis Au Yeung, Rosalind C. Lee, Victor Ambros, Eric G. Moss
The C. Elegans Heterochronic Gene Lin-46 Affects Developmental Timing At Two Larval Stages And Encodes A Relative Of The Scaffolding Protein Gephyrin, A. S.-R. Pepper, Jill E. Mccane, Kevin Kemper, Dennis Au Yeung, Rosalind C. Lee, Victor Ambros, Eric G. Moss
Dartmouth Scholarship
The succession of developmental events in the C. elegans larva is governed by the heterochronic genes. When mutated, these genes cause either precocious or retarded developmental phenotypes, in which stage-specific patterns of cell division and differentiation are either skipped or reiterated, respectively. We identified a new heterochronic gene, lin-46, from mutations that suppress the precocious phenotypes caused by mutations in the heterochronic genes lin-14 and lin-28. lin-46 mutants on their own display retarded phenotypes in which cell division patterns are reiterated and differentiation is prevented in certain cell lineages. Our analysis indicates that lin-46 acts at a step immediately downstream …
Rpb4p, A Subunit Of Rna Polymerase Ii, Mediates Mrna Export During Stress, Marganit Farago, Tal Nahari, Christopher Hammel, Charles N. Cole, Mordechai Choder
Rpb4p, A Subunit Of Rna Polymerase Ii, Mediates Mrna Export During Stress, Marganit Farago, Tal Nahari, Christopher Hammel, Charles N. Cole, Mordechai Choder
Dartmouth Scholarship
Changes in gene expression represent a major mechanism by which cells respond to stress. We and other investigators have previously shown that the yeast RNA polymerase II subunit Rpb4p is required for transcription under various stress conditions, but not under optimal growth conditions. Here we show that, in addition to its role in transcription, Rpb4p is also required for mRNA export, but only when cells are exposed to stress conditions. The roles of Rpb4p in transcription and in mRNA export can be uncoupled genetically by specific mutations in Rpb4p. Both functions of Rpb4p are required to maintain cell viability during …
Erv14p Directs A Transmembrane Secretory Protein Into Copii-Coated Transport Vesicles, Jacqueline Powers, Charles Barlowe
Erv14p Directs A Transmembrane Secretory Protein Into Copii-Coated Transport Vesicles, Jacqueline Powers, Charles Barlowe
Dartmouth Scholarship
Erv14p is a conserved integral membrane protein that traffics in COPII-coated vesicles and localizes to the early secretory pathway in yeast. Deletion of ERV14 causes a defect in polarized growth because Axl2p, a transmembrane secretory protein, accumulates in the endoplasmic reticulum and is not delivered to its site of function on the cell surface. Herein, we show that Erv14p is required for selection of Axl2p into COPII vesicles and for efficient formation of these vesicles. Erv14p binds to subunits of the COPII coat and binding depends on conserved residues in a cytoplasmically exposed loop domain of Erv14p. When mutations are …
Sec34p, A Protein Required For Vesicle Tethering To The Yeast Golgi Apparatus, Is In A Complex With Sec35p, Susan M. Vanrheenen, Xiaochun Cao, Stephanie K. Sapperstein, Elbert C. Chiang, Vladimir V. Lupashin, Charles Barlowe, M. Gerard Waters
Sec34p, A Protein Required For Vesicle Tethering To The Yeast Golgi Apparatus, Is In A Complex With Sec35p, Susan M. Vanrheenen, Xiaochun Cao, Stephanie K. Sapperstein, Elbert C. Chiang, Vladimir V. Lupashin, Charles Barlowe, M. Gerard Waters
Dartmouth Scholarship
A screen for mutants of Saccharomyces cerevisiae secretory pathway components previously yielded sec34, a mutant that accumulates numerous vesicles and fails to transport proteins from the ER to the Golgi complex at the restrictive temperature (Wuestehube, L.J., R. Duden, A. Eun, S. Hamamoto, P. Korn, R. Ram, and R. Schekman. 1996. Genetics. 142:393–406). We find that SEC34 encodes a novel protein of 93-kD, peripherally associated with membranes. The temperature-sensitive phenotype of sec34-2 is suppressed by the rab GTPase Ypt1p that functions early in the secretory pathway, or by the dominant form of the ER to Golgi complex target-SNARE …
Cloning Of Human Acetyl-Coa Carboxylase-Beta And Its Unique Features., Joohun Ha, Jung-Kee Lee, Kyung-Sup Kim, Lee A. Witters, Ki-Han Kim
Cloning Of Human Acetyl-Coa Carboxylase-Beta And Its Unique Features., Joohun Ha, Jung-Kee Lee, Kyung-Sup Kim, Lee A. Witters, Ki-Han Kim
Dartmouth Scholarship
Acetyl-CoA carboxylase, which has a molecular mass of 265 kDa (ACC-alpha), catalyzes the rate-limiting step in the biosynthesis of long-chain fatty acids. In this study we report the complete amino acid sequence and unique features of an isoform of ACC with a molecular mass of 275 kDa (ACC-beta), which is primarily expressed in heart and skeletal muscles. In these tissues, ACC-beta may be involved in the regulation of fatty acid oxidation, rather than fatty acid biosynthesis. ACC-beta contains an amino acid sequence at the N terminus which is about 200 amino acids long and may be uniquely related to the …
A Novel Iron-Regulated Metal Transporter From Plants Identified By Functional Expression In Yeast., David Eide, Margaret Broderius, Jeanette Fett, Mary Lou Guerinot
A Novel Iron-Regulated Metal Transporter From Plants Identified By Functional Expression In Yeast., David Eide, Margaret Broderius, Jeanette Fett, Mary Lou Guerinot
Dartmouth Scholarship
Iron is an essential nutrient for virtually all organisms. The IRT1 (iron-regulated transporter) gene of the plant Arabidopsis thaliana, encoding a probable Fe(II) transporter, was cloned by functional expression in a yeast strain defective for iron uptake. Yeast expressing IRT1 possess a novel Fe(II) uptake activity that is strongly inhibited by Cd. IRT1 is predicted to be an integral membrane protein with a metal-binding domain. Data base comparisons and Southern blot analysis indicated that IRT1 is a member of a gene family in Arabidopsis. Related sequences were also found in the genomes of rice, yeast, nematodes, and humans. In Arabidopsis, …
Circadian Clock Locus Frequency: Protein Encoded By A Single Open Reading Frame Defines Period Length And Temperature Compensation., Benjamin D. Aronson, Keith A. Johnson, Jay C. Dunlap
Circadian Clock Locus Frequency: Protein Encoded By A Single Open Reading Frame Defines Period Length And Temperature Compensation., Benjamin D. Aronson, Keith A. Johnson, Jay C. Dunlap
Dartmouth Scholarship
The frequency (frq) locus encodes a key component, a state variable, in a cellular oscillator generating circadian rhythmicity. Two transcripts have been mapped to this region, and data presented here are consistent with the existence of a third transcript. Analysis of cDNA clones and clock mutants from this region focuses attention on one transcript encoding a protein. FRQ, which is a central clock component: (i) mutations in all of the semidominant frq alleles are the result of single amino acid substitutions and map to the open reading frame (ORF) encoding FRQ; (ii) deletion of this ORF, or a frameshift mutation …
Differential Regulation Of Collagenase Gene Expression By Retinoic Acid Receptors--Alpha, Beta And Gamma, Luying Pan, Stephen H. Chamberlain, David T. Auble, Constance E. Brinckerhoff
Differential Regulation Of Collagenase Gene Expression By Retinoic Acid Receptors--Alpha, Beta And Gamma, Luying Pan, Stephen H. Chamberlain, David T. Auble, Constance E. Brinckerhoff
Dartmouth Scholarship
The mechanisms involved in retinoic acid (RA)-mediated regulation of the collagenase gene in a rabbit synovial fibroblast cell line (HIG82) were investigated. When HIG82 cells are cotransfected with expression vectors containing cDNAs for retinoic acid receptor (RAR) α1, β2, or γ1 and collagenase promoter-driven CAT reporter constructs, only RAR-γ1 represses basal CAT expression upon RA treatment, while RAR-α1, β2, and γ1 all suppress phorbol-induced CAT expression. Thus, transcriptional regulation of collagenase by RA is mediated by RARs in an RAR-type specific manner. Using mutatlonal and deletional analysis, we find that interaction between elements within 182 bp collagenase promoter plays an …