Overview of Transcription

RNA is initially synthesized using a DNA template in the process called 

As is the case with DNA biosynthesis, the RNA chain grows from the 5 to the 

The nucleotide at the 5 end of the chain retains its triphosphate group (abbreviated ppp). 

The enzyme uses one strand of the DNA as the template for RNA synthesis. The base sequence of the DNA contains signals for initiation and termination of RNA synthesis. The enzyme binds to the template strand and moves along it in the 3 -to-5 direction. 

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Figure 3 provides a very general overview of transcriptional activation in response to a PPAR ligand. Fig. 3a shows the schematic representation of a PPAR target gene in the absence of PPAR ligand. Co-repressor proteins bound to both unliganded PPAR and RXR... 

Jennings P, Limonciel A, Felice L, Leonard MO (2013) An overview of transcriptional regulation in response to toxicological insult. Arch Toxicol 87 49-72... 

Figure 14.13 Overview of the concept of the antisense approach the end goal is the prevention of expression of a particular gene product (invariably a protein) by either blocking the transcription or translation of that gene...

Figure 21.17 Overview of the regulation of the genes that express three proteins essential for DNA synthesis. The Rb gene expresses Rb which inactivates the transcription factor by forming a complex. Phosphorylation of the Rb protein by a cell cycle kinase causes dissociation of complex and release of transcription factor, which is now active and stimulates expression of the three genes. THFR, tetra hydrofolate reductase. See chapter 20 for details of the actions of cyclins, DNA polymerase and THFR in the cell cycle.

Finally, in this brief overview of lymphocyte defects, mention should be made of mutations affecting major histocompatibility-complex (MHC) Class II molecules. These mutations affect a multiprotein transcription factor complex that regulates the expression of MHC Class II molecules (121). Affected patients have undetectable levels of MHC Class II antigens HLA-DP, DQ, and DR on the surface of monocytes and B cells. Lack of these antigen-presenting molecules leads to impaired immune response. Affected individuals have moderate lymphopenia with a severely reduced number of CD4+ T cells and normal or increased numbers of CD8+ T cells. Since MHC molecules in the thymic epithelium play a key role in positive and negative selection of primitive T cells, selection of competent T cells is also affected in the absence of MHC Class II antigens. 

Fig. 9.12. Overview of the Ras signaling pathway. Signals from at least three major signaling pathways meet at the Ras protein. Activation of the Ras protein may be initiated by receptor tyrosine kinases, by G-protein-coupled receptors and by receptors with associated tyrosine kinases. The nature of the communication between the Ras protein and receptors with associated tyrosine kinase or G-protein-coupled receptors is mostly unknown. From the activated Ras protein, the signal is passed to various effector molecules including members of the MEK kinases, PI3-kinase, pl20 GAP and Ral-GEFs. The best understood is the effector function of Raf kinase, which passes a signal to the transcription level via the MAP kinase pathway.

Kramer JA, Pettit SD, Amin RP et al. Overview on the application of transcription profiling using selected nephrotoxicants for toxicology assessment. Environ Health Perspect 2004 112 460-464. Newton RK, Aardema M, Aubrecht J. The utility of DNA microarrays for characterizing genotoxicity. Environ Health Perspect 2004 112 420 22. 

Transcript of an excellent talk given at the Lindesmith Center (New York) in March 2000. A straightforward overview of what MDMA is, what the potential risks of it are, what urban myths surround it, and what the therapeutic potential is. 

We begin by examining the interactions between proteins and DNA that are the key to transcriptional regulation. We next discuss the specific proteins that influence the expression of specific genes, first in prokaryotic and then in eukaryotic cells. Information about posttranscriptional and translational regulation is included in the discussion, where relevant, to provide a more complete overview of the rich complexity of regulatory mechanisms. 

Transcription in eukaryotes an overview (G5) Transcription of protein-coding genes in eukaryotes (G6) Regulation of transcription by RNA Pol II (G7)... 

Overview In eukaryotes, the product of transcription of a protein-coding gene is pre-... 

This has been a necessarily brief overview of the processes of replication, transcription, and translation. If you are interested in learning more, please consult a biochemistry textbook. 

Staining of consecutive sections with histochemical reagents for protein and antibodies against myrosinase showed that myrosin cells actually contain myrosinase (Fig. 4.2D,E).18,43,44 By electron microscopy immunogold labelling studies, the enzyme was localized to the interior of the vacuoles of the myrosin cells (Fig. 4.2F).18,40,41 It has also been shown by several in situ hybridization experiments that myrosinase transcripts are located in these cells (Fig. 4.2G),6 demonstrating that the cellular localization of myrosinase is due to transcriptional regulation and not to a transport process. No evidence for transport of myrosinase currently exists. These methods for detection and identification of myrosin cells and myrosinase expression are illustrated (Fig. 4.2). For a historical overview of myrosinase localization studies, see Bones and Rossiter.45... 

Fig. 1. Schematic overview of copper trafficking and homeostasis inside the yeast cell. The actions of Mad and Ace 1, copper-dependent metalloregulatory transcription factors, control the production of copper import [copper transporter (Ctr) and reductase (Fre)] and detoxification/sequestration [metallothionein (MT)] machineries, respectively. Three chaperone-mediated delivery pathways are shown. Atxl shuttles Cu(I) to the secretory pathway P-type ATPase Ccc2 (right). CCS delivers Cu(I) to the cytoplasmic enzyme copper-zinc superoxide dismutase (SOD) (left). Coxl7 shuttles Cu(I) to cytochrome c oxidase (CCO) in the mitochondria (bottom). Mitochondrial proteins Scol and Sco2 may also play a role in copper delivery to the CuA and CuB sites of CCO. Copper metabolism and iron metabolism are linked through the actions of Fet3, a copper-containing ferroxidase required to bring iron into the cell (lower right) (see text).

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