Determining the RAD51-DNA Nucleoprotein Filament Structure and Function by Cryo-Electron Microscopy

2018 ◽  
pp. 179-199 ◽  
Author(s):  
Lingyun Zhao ◽  
Jingfei Xu ◽  
Weixing Zhao ◽  
Patrick Sung ◽  
Hong-Wei Wang
Keyword(s):  
Electron Microscopy ◽  
Structure And Function ◽  
Cryo Electron Microscopy ◽  
Filament Structure ◽  
And Function

scholarly journals Structure and function of yeast Lso2 and human CCDC124 bound to hibernating ribosomes

2020 ◽  
Author(s):  
Jennifer N. Wells ◽  
Robert Buschauer ◽  
Timur Mackens-Kiani ◽  
Katharina Best ◽  
Hanna Kratzat ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Stationary Phase ◽  
Large Subunit ◽  
Structure And Function ◽  
Nutrient Deprivation ◽  
Recycling System ◽  
Cryo Electron Microscopy ◽  
And Function

AbstractCells adjust to nutrient deprivation by reversible translational shut down. This is accompanied by maintaining inactive ribosomes in a hibernation state, where they are bound by proteins with inhibitory and protective functions. In eukaryotes, such a function was attributed to Stm1 (SERBP1 in mammals), and recently Lso2 (CCDC124 in mammals) was found to be involved in translational recovery after starvation from stationary phase. Here, we present cryo-electron microscopy (cryo-EM) structures of translationally inactive yeast and human ribosomes. We found Lso2/CCDC124 accumulating on idle ribosomes in the non-unrotated state, in contrast to Stm1/SERBP1-bound ribosomes, which display a rotated state. Lso2/CCDC124 bridges the decoding sites of the small with the GTPase-activating center of the large subunit. This position allows accommodation of the Dom34-dependent ribosome recycling system, which splits Lso2-containing but not Stm1-containing ribosomes. We propose a model in which Lso2 facilitates rapid translation reactivation by stabilizing the recycling-competent state of inactive ribosomes.

Use of human autoantibodies and immunoelectron microscopy to study structure and function of the nucleolus and nuclear bodies

1992 ◽  
Vol 50 (1) ◽  
pp. 506-507
Author(s):  
Robert L. Ochs
Keyword(s):  
Electron Microscopy ◽  
Structure And Function ◽  
Nuclear Bodies ◽  
Nuclear Interior ◽  
Coiled Bodies ◽  
Interchromatin Granules ◽  
And Function ◽  
Conventional Electron Microscopy ◽  
Perichromatin Granules ◽  
Perichromatin Fibrils

By conventional electron microscopy, the formed elements of the nuclear interior include the nucleolus, chromatin, interchromatin granules, perichromatin granules, perichromatin fibrils, and various types of nuclear bodies (Figs. 1a-c). Of these structures, all have been reasonably well characterized structurally and functionally except for nuclear bodies. The most common types of nuclear bodies are simple nuclear bodies and coiled bodies (Figs. 1a,c). Since nuclear bodies are small in size (0.2-1.0 μm in diameter) and infrequent in number, they are often overlooked or simply not observed in any random thin section. The rat liver hepatocyte in Fig. 1b is a case in point. Historically, nuclear bodies are more prominent in hyperactive cells, they often occur in proximity to nucleoli (Fig. 1c), and sometimes they are observed to “bud off” from the nucleolar surface.

Crystal Structures of Fragments D and Double-D from Fibrinogen and Fibrin

1999 ◽  
Vol 82 (08) ◽  
pp. 271-276 ◽  
Author(s):  
Glen Spraggon ◽  
Stephen Everse ◽  
Russell Doolittle
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Crystal Structures ◽  
Structure And Function ◽  
X Ray ◽  
Long Period ◽  
And Function

IntroductionAfter a long period of anticipation,1 the last two years have witnessed the first high-resolution x-ray structures of fragments from fibrinogen and fibrin.2-7 The results confirmed many aspects of fibrinogen structure and function that had previously been inferred from electron microscopy and biochemistry and revealed some unexpected features. Several matters have remained stubbornly unsettled, however, and much more work remains to be done. Here, we review several of the most significant findings that have accompanied the new x-ray structures and discuss some of the problems of the fibrinogen-fibrin conversion that remain unresolved. * Abbreviations: GPR—Gly-Pro-Arg-derivatives; GPRPam—Gly-Pro-Arg-Pro-amide; GHRPam—Gly-His-Arg-Pro-amide

Morphological and Biochemical Features Affecting the Antithrombotic Properties of the Aorta in Adult Rabbits and Rabbit Pups

1998 ◽  
Vol 79 (05) ◽  
pp. 1034-1040 ◽  
Author(s):  
E. Nitschmann ◽  
L. Berry ◽  
S. Bridge ◽  
M. W. C. Hatton ◽  
M. Richardson ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Gel Electrophoresis ◽  
Arterial Wall ◽  
Structure And Function ◽  
Wall Structure ◽  
Matrix Structure ◽  
Antithrombotic Activity ◽  
Antithrombin Activity ◽  
And Function ◽  
Biochemical Features

SummaryWe hypothesised that there are important physiologic differences in arterial wall structure and function with respect to antithrombotic activity in the very young (pre-puberty) compared to adults. Electron microscopy, gel electrophoresis, and activity assays were used to examine differences in aorta structure and function comparing prepubertal rabbits (pups) to adult rabbits. Differences in endothelial function, extracellular matrix structure, proteoglycan (PG) distribution and glycosaminoglycan (GAG) content and function were shown. In both intima and media, total PG, chondroitin sulfate (CS) PG and heparan sulfate (HS) PG content were significantly increased in pups compared to adult rabbits. These findings corresponded to increased concentrations by mass analyses of CS GAG and DS GAG in aortas from pups. There was also a significant increase in antithrombin activity in pups due to HS GAG. In conclusion, differences in both structure and antithrombin activity of aortas from pups compared to adult rabbits suggest that young arteries may have greater antithrombotic potential that is, at least in part, related to increased HS GAG.

The beaded filament of the eye lens: an unexpected key to intermediate filament structure and function

1996 ◽  
Vol 6 (4) ◽  
pp. 123-126 ◽  
Author(s):  
Roy A. Quinlan ◽  
Jane M. Carte ◽  
Aileen Sandilands ◽  
Alan R. Prescott
Keyword(s):  
Intermediate Filament ◽  
Structure And Function ◽  
Eye Lens ◽  
Filament Structure ◽  
And Function

scholarly journals The structure of the yeast Ctf3 complex

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Stephen M Hinshaw ◽  
Andrew N Dates ◽  
Stephen C Harrison
Keyword(s):  
Electron Microscopy ◽  
Cell Cycle ◽  
High Resolution ◽  
Atomic Model ◽  
Kinetochore Assembly ◽  
Cryo Electron Microscopy ◽  
Molecular Interpretation ◽  
Spindle Microtubules ◽  
And Function ◽  
Assembly Site

Kinetochores are the chromosomal attachment points for spindle microtubules. They are also signaling hubs that control major cell cycle transitions and coordinate chromosome folding. Most well-studied eukaryotes rely on a conserved set of factors, which are divided among two loosely-defined groups, for these functions. Outer kinetochore proteins contact microtubules or regulate this contact directly. Inner kinetochore proteins designate the kinetochore assembly site by recognizing a specialized nucleosome containing the H3 variant Cse4/CENP-A. We previously determined the structure, resolved by cryo-electron microscopy (cryo-EM), of the yeast Ctf19 complex (Ctf19c, homologous to the vertebrate CCAN), providing a high-resolution view of inner kinetochore architecture (Hinshaw and Harrison, 2019). We now extend these observations by reporting a near-atomic model of the Ctf3 complex, the outermost Ctf19c sub-assembly seen in our original cryo-EM density. The model is sufficiently well-determined by the new data to enable molecular interpretation of Ctf3 recruitment and function.

Evaluation of neutrophil structure and function by electron microscopy: cytochemical studies

1999 ◽  
Vol 232 (1-2) ◽  
pp. 169-178 ◽  
Author(s):  
John M Robinson ◽  
Toshihiro Kobayashi ◽  
Harumichi Seguchi ◽  
Toshihiro Takizawa
Keyword(s):  
Electron Microscopy ◽  
Structure And Function ◽  
And Function

scholarly journals Canalicular domain structure and function in matrix-free hepatic spheroids

2020 ◽  
Vol 8 (1) ◽  
pp. 485-496 ◽  
Author(s):  
Vikas Raj Sharma ◽  
Ananya Shrivastava ◽  
Benoit Gallet ◽  
Elizaveta Karepina ◽  
Peggy Charbonnier ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Fluorescence Microscopy ◽  
Light Sheet ◽  
Structure And Function ◽  
Bile Canaliculi ◽  
Combined Use ◽  
3D Electron Microscopy ◽  
And Function ◽  
Matrix Free ◽  
Light Sheet Fluorescence Microscopy

The combined use of light sheet fluorescence microscopy and 3D electron microscopy enables to reveal the fine details of bile canaliculi structure and function in matrix-free hepatic spheroids.

Effect of basolateral acidification on the frog oxynticopeptic cell

1990 ◽  
Vol 259 (4) ◽  
pp. G564-G570 ◽  
Author(s):  
S. Arvidsson ◽  
K. Carter ◽  
A. Yanaka ◽  
S. Ito ◽  
W. Silen
Keyword(s):  
Electron Microscopy ◽  
Gastric Mucosa ◽  
Light And Electron Microscopy ◽  
Structure And Function ◽  
Intracellular Acidification ◽  
Intracellular Acidosis ◽  
Normal Morphology ◽  
And Function ◽  
Oxynticopeptic Cells

The effects of intracellular acidosis induced by acidification of the basolateral (nutrient) perfusate on the structure and function of the oxynticopeptic cell were studied in in vitro frog gastric mucosa. Changing the pH of the unbuffered nutrient perfusate (UNB) from 7.2 to 3.5 acidified the oxynticopeptic cell with no change in potential difference (PD) or resistance (R). Intracellular pH (pHi), PD, and R were 7.05 +/- 0.01, 16 +/- 1 mV, 165 +/- 7 omega.cm2 before and 6.44 +/- 0.01, 16 +/- 2 mV, 170 +/- 9 omega.cm2 after nutrient acidification. Acid secretion (H+) increased from 0.86 +/- 0.07 to 1.88 +/- 0.18 mu eq.cm-2.h-1. Addition of forskolin to tissues perfused with nutrient pH (pHn) 3.5 decreased PD to 2 +/- 2 mV and further increased H+ to 3.07 +/- 0.19 mu eq.cm-2.h-1. By light and electron microscopy oxynticopeptic cells perfused with UNB, pHn 3.5, appeared normal. Oxynticopeptic cells in tissues pretreated with omeprazole and then exposed to UNB, pHn 3.5, had extensive morphological damage. On increasing the pH of the nutrient perfusate from 3.5 to 7.2 there was prompt recovery of pHi in untreated and forskolin-stimulated mucosae (pHi 6.87 +/- 0.06 and 6.85 +/- 0.04) but no recovery of pHi in tissues pretreated with omeprazole or cimetidine (pHi 6.26 +/- 0.04 and 6.44 +/- 0.06, n = 6, 30 min after reexposure to UNB, pHn 7.2). We conclude that in a secreting mucosa intracellular acidification of the oxynticopeptic cell to pHi 6.4 is associated with normal morphology, PD, R, and increased H+, and that intracellular acidosis is not de facto deleterious.

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