Transcription-translation complex

In bacterial cells mRNA is combined with ribosomes immediately after its synthesis (Stent, 1966). In this way the ribosomes perhaps have a role in the liberation of the newly formed mRNA from the DNA template. As a result, a transcription-translation complex is formed containing DNA, RNA polymerase, the newly synthesized growing RNA chain, and ribosomes translating mRNA. The transcription and translation are coupled. On the other hand in eukaryotes transcription and translation are separated in... 

Since the synthesis of both classes of these MTs has not yet been shown to be specifically regulated by one metal rather than another, any specificity of function may result from molecular recognition in the binding of ions to these polypeptides. It is clear that in M. guttatus, Cu, but not Cd, is bound to certain proteins perhaps because of the different chemical properties of the ions (although as yet transcriptional/translational control of synthesis of these proteins cannot be totally rejected). Furthermore, although both Cu and Cd form PC complexes, it is possible that PC complexes with essential metal ions could be processed differently from those with non-essential metal ions. 

COX-2 and iNOS. Some steroid hormone receptors complexed with their specific hormone ligand act as DNA-binding transactivators to switch on transcription of particular genes. However, in the hormone-free state these proteins can act as repressors and block initiation of transcription of these genes. DNA and associated transcription, translation and replication processes are similar in plants and non-plant eukaryotes. Nevertheless, some plants elaborate DNA binding compounds or compounds that otherwise interfere with gene expression and DNA replication (Tables 9.1—9.4). 

The regulation of the synthesis of the polypeptides of PS II appears to be particularly complex, with evidence for regulation at transcriptional, translational and post-translational levels. The synthesis of the individual polypeptides does not appear to be tightly coordinated, with certain polypeptides accumulating in the absence of other PS II polypeptides under a variety of experimental conditions. The synthesis of a functional PS II complex is strongly dependent on light, both for its effect on the transcription of PS II genes and for its absolute requirement for Chi synthesis. 

The synthesis of the polypeptides of the core complex takes place exclusively in the chloroplasts, as indicated by synthesis in isolated chloroplasts or by translation of chloroplast RNA in vitro. Regulation of the synthesis appears to operate at transcriptional, translational and post-translational levels, with light playing a major role. 

Regulation of CKIs occurrs by transcriptional, translational, proteolytic and localiza-tional mechanisms, and multiple input signals have been identified that influence these processes in a complex relationship. 

The complex arrangements that regulate gene transcription, translation, and protein function are all potential mechanisms through which disease could act, and so analysis of potential disease alleles needs to evaluate almost every eventuality. Figure... 

The previous sections have introduced the major participants in protein synthesis—mRNA, aminoacylated tRNAs, and ribosomes containing large and small rRNAs. We now take a detailed look at how these components are brought together to carry out the biochemical events leading to formation of polypeptide chains on ribosomes. Similar to transcription, the complex process of translation can be divided into three stages—initiation, elongation, and termination—which we consider in order. We focus our description on translation in eukaryotic cells, but the mechanism of translation is fundamentally the same in all cells. 

Ribosome Display. This cell-free display system uses the same principle as the phage-display systems in bacteria. The phenotype and genotype of a peptide are linked together and, therefore, can be simultaneously selected based on the function of the peptide. However, the linkage is a physical one in that the genetic material is covalently linked to its encoded product in the formation of an antibody-ribosome-mRNA (ARM) complex through in vitro transcription/translation [59]. 

Edmondson, R. D., T. M. Vondriska, K. J. Biederman, J. Zhang, R. C. Jones, Y. Zheng, D. L. Allen, J. X. Xiu, E. M. Cardwell, M. R. Pisano, and P. Ping. 2002, Protein kinase C epsilon signaling complexes include metabolism- and transcription/translation-related proteins complimentary separation techniques with LC/MS/MS. Mol.Cell.Proteomics 1 421-433. 

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