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Articles 1 - 10 of 10
Full-Text Articles in Biochemistry, Biophysics, and Structural Biology
Transitions In Histone Acetylation Reveal Boundaries Of Three Separately Regulated Neighboring Loci, Michael D. Litt, Melanie A. Simpson, Felix Recillas-Targa, Marie-Noelle Prioleau, Gary Felsenfeld
Transitions In Histone Acetylation Reveal Boundaries Of Three Separately Regulated Neighboring Loci, Michael D. Litt, Melanie A. Simpson, Felix Recillas-Targa, Marie-Noelle Prioleau, Gary Felsenfeld
Department of Biochemistry: Faculty Publications
We have studied developmentally regulated patterns of histone acetylation at high resolution across ~54 kb of DNA containing three independently regulated but neighboring genetic loci. These include a folate receptor gene, a 16 kb condensed chromatin region, the chicken β-globin domain and an adjacent olfactory receptor gene. Within these regions the relative levels of acetylation appear to fall into three classes. The condensed chromatin region maintains the lowest acetylation at every developmental stage. Genes that are inactive show similarly low levels, but activation results in a dramatic increase in acetylation. The highest levels of acetylation are seen at regulatory sites …
Correlation Between Histone Lysine Methylation And Developmental Changes At The Chicken Β-Globin Locus, Michael D. Litt, Melanie A. Simpson, Miklos Gaszner, D. David Allis, Gary Felsenfeld
Correlation Between Histone Lysine Methylation And Developmental Changes At The Chicken Β-Globin Locus, Michael D. Litt, Melanie A. Simpson, Miklos Gaszner, D. David Allis, Gary Felsenfeld
Department of Biochemistry: Faculty Publications
Methylation of histones at specific residues plays an important role in transcriptional regulation. Chromatin immunoprecipitation of dimethylated lysine 9 on histone H3 across 53 kilobases of the chicken β-globin locus during erythropoiesis shows an almost complete anticorrelation between regions of elevated lysine 9 methylation and acetylation. Lysine 9 is methylated most over constitutive condensed chromatin and developmentally inactive globin genes. In contrast, lysine 4 methylation of histone H3 correlates with H3 acetylation. These results lead us to propose a mechanism by which the insulator in the β-globin locus can protect the globin genes from being silenced by adjacent condensed chromatin.
Reversible Phosphorylation Of Photosynthetic Pep Carboxylase: Studies On C4-Leaf Pp2a And Recombinant Pepc-Kinase From Cam-Induced Mesembryanthemum Crystallinum, L. Dong, N. V. Ermolova, M. A. Cushman, T. Taybi, J. C. Cushman, Raymond Chollet
Reversible Phosphorylation Of Photosynthetic Pep Carboxylase: Studies On C4-Leaf Pp2a And Recombinant Pepc-Kinase From Cam-Induced Mesembryanthemum Crystallinum, L. Dong, N. V. Ermolova, M. A. Cushman, T. Taybi, J. C. Cushman, Raymond Chollet
Department of Biochemistry: Faculty Publications
The activity and allosteric properties of plant PEPC are controlled posttranslationally by specific reversible phosphorylation of a strictly conserved Ser residue near the N-terminus. This up/down-modulation is catalyzed by a transcriptionally regulated, seemingly dedicated Ser/Thr kinase (PpcK) and an opposing Ser/Thr phosphatase (PP2A). We have now partially purified and characterized the native form of this largely “neglected” PP2A from maize leaves using various chromatographic and affinity matrices, and C4 [32P]PEPC as substrate (Dong et al., 2001, Planta [in press]). The results indicate that the C4-leaf holoenzyme is analogous to yeast and mammalian PP2As in regards …
Unexpected Post-Translational Modifications And Novel Sequence-Structure Relationships Revealed By The Crystal Structure Of Chlamydomonas Reinhardtii Rubisco, T. C. Taylor, A. Backlund, R. J. Spreitzer, I. Andersson
Unexpected Post-Translational Modifications And Novel Sequence-Structure Relationships Revealed By The Crystal Structure Of Chlamydomonas Reinhardtii Rubisco, T. C. Taylor, A. Backlund, R. J. Spreitzer, I. Andersson
Department of Biochemistry: Faculty Publications
The crystal structure of Rubisco from Chlamydomonas reinhardtii has been solved to 1.4 Å resolution. In addition to clear electron density for the carbamate on lys-201, the active site magnesium ion and the inhibitor 2-CABP, there was unexpected but unambiguous electron density for further specific post-translational modification. The N-terminus of the mature small subunit is methylated. The large subunit contains two methylcysteine residues (256 & 369) and two hydroxyproline residues (104 & 151). The small subunit from Chlamydomonas shows a structure more similar to that of the higher green plants than that from other algae of known structure. An extensive …
Can Negligible Levels Of Rubisco Activase, Be The Reason For Decreased Rubisco Activity Levels In Guard Cells?, S. Madhavan, P. Echtenkamp
Can Negligible Levels Of Rubisco Activase, Be The Reason For Decreased Rubisco Activity Levels In Guard Cells?, S. Madhavan, P. Echtenkamp
Department of Biochemistry: Faculty Publications
Rubisco in guard cell chloroplasts has been a subject of controversy for decades. Several studies have unequivocally confirmed not only the presence of Rubisco in guard cells but also found it to be catalytically active. Based on a cell basis, the amount of Rubisco in guard cells is suggested to be in the range of 0.6 to 1.4 % whereas its activity is reported to be in the range of 0.35 to 0.5%, of a mesophyll cell. This low activity may be due a) to a low Rubisco content, and/or, b) to either the absence or an inactive functional activation …
Selenoprotein Oxidoreductase With Specificity For Thioredoxin And Glutathione Systems, Qi-An Sun, Leo Kirnarsky, Simon Sherman, Vadim N. Gladyshev
Selenoprotein Oxidoreductase With Specificity For Thioredoxin And Glutathione Systems, Qi-An Sun, Leo Kirnarsky, Simon Sherman, Vadim N. Gladyshev
Department of Biochemistry: Faculty Publications
Thioredoxin (Trx) and glutathione (GSH) systems are considered to be two major redox systems in animal cells. They are reduced by NADPH via Trx reductase (TR) or oxidized GSH (GSSG) reductase and further supply electrons for deoxyribonucleotide synthesis, antioxidant defense, and redox regulation of signal transduction, transcription, cell growth, and apoptosis. We cloned and characterized a pyridine nucleotide disulfide oxidoreductase, Trx and GSSG reductase (TGR), that exhibits specificity for both redox systems. This enzyme contains a selenocysteine residue encoded by the TGA codon. TGR can reduce Trx, GSSG, and a GSH-linked disulfide in in vitro assays. This unusual substrate specificity …
The Cia5 Gene Controls Formation Of The Carbon Concentrating Mechanism In Chlamydomonas Reinhardtii, Youbin Xiang, Jun Zhang, Donald P. Weeks
The Cia5 Gene Controls Formation Of The Carbon Concentrating Mechanism In Chlamydomonas Reinhardtii, Youbin Xiang, Jun Zhang, Donald P. Weeks
Department of Biochemistry: Faculty Publications
Wild-type Chlamydomonas reinhardtii cells shifted from high concentrations (5%) of CO2 to low, ambient levels (0.03%) rapidly increase transcription of mRNAs from several CO2-responsive genes. Simultaneously, they develop a functional carbon concentrating mechanism that allows the cells to greatly increase internal levels of CO2 and HCO3. The cia5 mutant is defective in all of these phenotypes. A newly isolated gene, designated Cia5, restores transformed cia5 cells to the phenotype of wild-type cells. The 6,481-bp gene produces a 5.1-kb mRNA that is present constitutively in light in high and low CO2 both in …
Monoclonal Light Chain–Mesangial Cell Interactions: Early Signaling Events And Subsequent Pathologic Effects, William J. Russell, James Cardelli, Ed Harris, R. John Baier, Guillermo A. Herrera
Monoclonal Light Chain–Mesangial Cell Interactions: Early Signaling Events And Subsequent Pathologic Effects, William J. Russell, James Cardelli, Ed Harris, R. John Baier, Guillermo A. Herrera
Department of Biochemistry: Faculty Publications
Glomerulopathic monoclonal light chains (G-LC) interact with mesangial cells (MC), resulting in alterations of mesangial homeostasis. Early signaling events control mitogenic activities and cytokine production, which in turn participate in the subsequent pathologic events. Mesangial homeostasis is affected in two very different ways, depending on whether the G-LC is from a patient with light chain deposition disease (LCDD) or light chain–related amyloidosis (AL-Am). In contrast, tubulopathic (T)-LC chains from patients with myeloma cast nephropathy do not significantly interact with MC and result in no alterations in mesangial homeostasis. Therefore, understanding early events in the monoclonal LC–MC interactions is fundamental. MC …
The Wasp-Like Protein Scar Regulates Macropinocytosis, Phagocytosis And Endosomal Membrane Flow In Dictyostelium, David J. Seastone, Ed Harris, Lesly A. Temesvari, James E. Bear, Charles L. Saxe, James Cardelli
The Wasp-Like Protein Scar Regulates Macropinocytosis, Phagocytosis And Endosomal Membrane Flow In Dictyostelium, David J. Seastone, Ed Harris, Lesly A. Temesvari, James E. Bear, Charles L. Saxe, James Cardelli
Department of Biochemistry: Faculty Publications
Scar, a member of the WASp protein family, was discovered in Dictyostelium discoideum during a genetic screen for second-site mutations that suppressed a developmental defect. Disruption of the scar gene reduced the levels of cellular F-actin by 50%. To investigate the role of Scar in endocytosis, phagocytosis and endocytic membrane trafficking, processes that depend on actin polymerization, we have analyzed a Dictyostelium cell line that is genetically null for Scar. Rates of fluid phase macropinocytosis and phagocytosis are significantly reduced in the scar- cell-line. In addition, exocytosis of fluid phase is delayed in these cells and movement of fluid …
Rab11-Like Gtpase Associates With And Regulates The Structure And Function Of The Contractile Vacuole System In Dictyostelium, Ed Harris, Kunito Yoshida, James Cardelli, John Bush
Rab11-Like Gtpase Associates With And Regulates The Structure And Function Of The Contractile Vacuole System In Dictyostelium, Ed Harris, Kunito Yoshida, James Cardelli, John Bush
Department of Biochemistry: Faculty Publications
Screening of a cDNA library revealed the existence of a Dictyostelium cDNA encoding a protein 80% identical at the amino acid level to mammalian Rab11. Subcellular fractionation and immunofluorescence studies revealed that DdRab11 was exclusively associated with the ATPase proton pump-rich contractile vacuole membrane system, consisting of a reticular network and bladder-like vacuoles. Video microscopy of cells expressing GFP-DdRab11 revealed that this Rab was associated with contractile vacuolar bladders undergoing formation, fusion and expulsion of water. The association of DdRab11 with contractile vacuole membranes was disrupted when cells were exposed to either hypo-osmotic conditions or an inhibitor of the ATPase …