Structure and function of the 5'-flanking sequence of the human cytosolic selenium-dependent glutathione peroxidase gene (hgpx1).

AbstractThe small RNA-mediated immunity in bacteria depends on foreign RNA-activated and self RNA-inhibited enzymatic activities. The multi-subunit Type III-A CRISPR-Cas effector complex (Csm) exemplifies this principle, but its molecular basis for regulation remains unexplained. Recognition of the foreign RNA, or cognate target RNA (CTR), triggers its single-stranded deoxyribonuclease (DNase) and cyclic oligoadenylate (cOA) synthesis activities. The same activities remain dormant in the presence of the self-RNA, or noncognate target RNA (NTR) that differs from CTR only in its 3’-protospacer flanking sequence. Here we captured four structures of in vivo assembled Lactococcus lactis Csm (LlCsm) by electron cryomicroscopy representing both the active and the inactive states. Surprisingly, in absence of bound RNA, LlCsm largely forms a minimal assembly lacking the Csm2 subunit with a stably bound catalytic subunit Csm1. Comparison of the minimal LlCsm structure and activities, both in vitro and in vivo, with those of fully assembled LlCsm reveals a molecular mechanism responsible for the viral RNA-activated and self RNA-inhibited activity of Csm1 through protein dynamics.Graphic Art Summary

Download Full-text

Roles of p53 Family Structure and Function in Non-Canonical Response Element Binding and Activation

International Journal of Molecular Sciences ◽

10.3390/ijms20153681 ◽

2019 ◽

Vol 20 (15) ◽

pp. 3681 ◽

Cited By ~ 4

Author(s):

Bi-He Cai ◽

Chung-Faye Chao ◽

Hsiang-Chi Huang ◽

Hsueh-Yi Lee ◽

Reiji Kannagi ◽

...

Keyword(s):

Target Genes ◽

P53 Protein ◽

Consensus Sequence ◽

Family Members ◽

Structure And Function ◽

Nonspecific Binding ◽

Flanking Sequence ◽

P53 Family ◽

Core Sequence ◽

And Function

The p53 canonical consensus sequence is a 10-bp repeat of PuPuPuC(A/T)(A/T)GPyPyPy, separated by a spacer with up to 13 bases. C(A/T)(A/T)G is the core sequence and purine (Pu) and pyrimidine (Py) bases comprise the flanking sequence. However, in the p53 noncanonical sequences, there are many variations, such as length of consensus sequence, variance of core sequence or flanking sequence, and variance in number of bases making up the spacer or AT gap composition. In comparison to p53, the p53 family members p63 and p73 have been found to have more tolerance to bind and activate several of these noncanonical sequences. The p53 protein forms monomers, dimers, and tetramers, and its nonspecific binding domain is well-defined; however, those for p63 or p73 are still not fully understood. Study of p63 and p73 structure to determine the monomers, dimers or tetramers to bind and regulate noncanonical sequence is a new challenge which is crucial to obtaining a complete picture of structure and function in order to understand how p63 and p73 regulate genes differently from p53. In this review, we will summarize the rules of p53 family non-canonical sequences, especially focusing on the structure of p53 family members in the regulation of specific target genes. In addition, we will compare different software programs for prediction of p53 family responsive elements containing parameters with canonical or non-canonical sequences.

Download Full-text

Structure and function of neural networks in the retina

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100102213 ◽

1988 ◽

Vol 46 ◽

pp. 26-27

Author(s):

Peter Sterling

Keyword(s):

Ganglion Cells ◽

Three Dimensional ◽

Structure And Function ◽

Synaptic Connections ◽

Visual Axis ◽

One Dimensional ◽

Cat Retina ◽

Ultrathin Sections ◽

And Function ◽

Insight Into

The synaptic connections in cat retina that link photoreceptors to ganglion cells have been analyzed quantitatively. Our approach has been to prepare serial, ultrathin sections and photograph en montage at low magnification (˜2000X) in the electron microscope. Six series, 100-300 sections long, have been prepared over the last decade. They derive from different cats but always from the same region of retina, about one degree from the center of the visual axis. The material has been analyzed by reconstructing adjacent neurons in each array and then identifying systematically the synaptic connections between arrays. Most reconstructions were done manually by tracing the outlines of processes in successive sections onto acetate sheets aligned on a cartoonist's jig. The tracings were then digitized, stacked by computer, and printed with the hidden lines removed. The results have provided rather than the usual one-dimensional account of pathways, a three-dimensional account of circuits. From this has emerged insight into the functional architecture.

Download Full-text

Osseointegration interface of calcified bone and endosseous implants

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100130110 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1096-1097

Author(s):

K.E. Krizan ◽

J.E. Laffoon ◽

M.J. Buckley

Keyword(s):

Structure And Function ◽

Titanium Implants ◽

En Bloc ◽

Endosseous Implants ◽

Ultrastructural Studies ◽

The Past ◽

Cacodylate Buffer ◽

One Year ◽

And Function

With increase use of tissue-integrated prostheses in recent years it is a goal to understand what is happening at the interface between haversion bone and bulk metal. This study uses electron microscopy (EM) techniques to establish parameters for osseointegration (structure and function between bone and nonload-carrying implants) in an animal model. In the past the interface has been evaluated extensively with light microscopy methods. Today researchers are using the EM for ultrastructural studies of the bone tissue and implant responses to an in vivo environment. Under general anesthesia nine adult mongrel dogs received three Brånemark (Nobelpharma) 3.75 × 7 mm titanium implants surgical placed in their left zygomatic arch. After a one year healing period the animals were injected with a routine bone marker (oxytetracycline), euthanized and perfused via aortic cannulation with 3% glutaraldehyde in 0.1M cacodylate buffer pH 7.2. Implants were retrieved en bloc, harvest radiographs made (Fig. 1), and routinely embedded in plastic. Tissue and implants were cut into 300 micron thick wafers, longitudinally to the implant with an Isomet saw and diamond wafering blade [Beuhler] until the center of the implant was reached.

Download Full-text

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

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100122939 ◽

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.

Download Full-text

Depletion and Reconstitution of Active E. Coli Ribosomes

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100116826 ◽

1975 ◽

Vol 33 ◽

pp. 640-641

Author(s):

M. Boublik ◽

W. Hellmann ◽

F. Jenkins

Keyword(s):

Protein Biosynthesis ◽

Large Subunit ◽

High Resolution Electron Microscopy ◽

Small Subunit ◽

Structure And Function ◽

Biologically Active ◽

Biological Macromolecules ◽

E Coli ◽

Resolution Electron ◽

And Function

Correlations between structure and function of biological macromolecules have been studied intensively for many years, mostly by indirect methods. High resolution electron microscopy is a unique tool which can provide such information directly by comparing the conformation of biopolymers in their biologically active and inactive state. We have correlated the structure and function of ribosomes, ribonucleoprotein particles which are the site of protein biosynthesis. 70S E. coli ribosomes, used in this experiment, are composed of two subunits - large (50S) and small (30S). The large subunit consists of 34 proteins and two different ribonucleic acid molecules. The small subunit contains 21 proteins and one RNA molecule. All proteins (with the exception of L7 and L12) are present in one copy per ribosome.This study deals with the changes in the fine structure of E. coli ribosomes depleted of proteins L7 and L12. These proteins are unique in many aspects.

Download Full-text

The Laryngeal Epithelium in Reflux

Perspectives on Voice and Voice Disorders ◽

10.1044/vvd21.3.112 ◽

2011 ◽

Vol 21 (3) ◽

pp. 112-117 ◽

Cited By ~ 2

Author(s):

Elizabeth Erickson-Levendoski ◽

Mahalakshmi Sivasankar

Keyword(s):

Laryngopharyngeal Reflux ◽

Critical Role ◽

Structure And Function ◽

Laryngeal Disease ◽

Health And Disease ◽

And Function ◽

The Impact

The epithelium plays a critical role in the maintenance of laryngeal health. This is evident in that laryngeal disease may result when the integrity of the epithelium is compromised by insults such as laryngopharyngeal reflux. In this article, we will review the structure and function of the laryngeal epithelium and summarize the impact of laryngopharyngeal reflux on the epithelium. Research investigating the ramifications of reflux on the epithelium has improved our understanding of laryngeal disease associated with laryngopharyngeal reflux. It further highlights the need for continued research on the laryngeal epithelium in health and disease.

Download Full-text