RNA functions

Not all the base-pairing is of the Watson-Crick variety, either. For example, G-U, U-U, and A-G base pairs are relatively common. These interactions contribute to the wide variety of structures that RNA can assume. RNA molecules also contain modified nucleosides, and in some cases, quite complicated ones. These are synthesized post-transcriptionally as part of the maturation process of RNA and serve to fine-tune RNA functions. 

Most RNAs function in an information carrying and/or processing mode in the cell. As Chapter 4 of Volume 1 of this series pointed out, the overall information processes of the cell are given in the Central Dogma of Molecular Biology DNA makes RNA makes Protein. RNA is involved as a carrier of information, as translator or adaptor of RNA information into protein information, and as catalyst for the synthesis of the peptide bond. 

Eukaryotic mRNAs often have long 3 untranslated sequences— sequences that follow the stop codon for the protein they encode. These mRNAs generally conclude with a sequence of up to 200 adenosines, the polyadenylic acid (polyA) sequence at the 3 end. This sequence isn t coded by the DNA template for the gene it is added post-transcriptionally. Not all mRNAs are polyadenylated. For example, histone mRNAs lack polyA tails. Polyadenylation seems to play a role in regulating the stability of mRNAs. An early event in the breakdown of some mRNAs is the removal of their polyA tails. 

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Weber, L. A., Hickey, E.D., Nuss, D.L. Bayloni, C. (1977). 5 -terminal 7-methyl-guanosine and messenger RNA function influence of potassium concentration on translation in vitro. Journal of Biological Chemistry, 252, 4007-10. 

Efforts were concentrated mainly on the backbone of RNA, i.e., the sequence phosphate - D-ribose - phosphate - D-ribose - phosphate, which needed to be simplified without losing the most important RNA functions, such as base pairing and information transfer. 

Doxorubicin thymidine, the other interferes with RNA function Binds to DNA and uncoils DNA... 

Many examples of catalytic nucleic acids obtained by in vitro selection demonstrate that reactions catalyzed by ribozymes are not restricted to phosphodiester chemistry. Some of these ribozymes have activities that are highly relevant for theories of the origin of life. Hager et al. have outlined five roles for RNA to be verified experimentally to show that this transition could have occurred during evolution [127]. Four of these RNA functionalities have already been proven Its ability to specifically complex amino acids [128-132], its ability to catalyze RNA aminoacylation [106, 123, 133], acyl-transfer reactions [76, 86], amide-bond formation [76,77], and peptidyl transfer [65,66]. The remaining reaction, amino acid activation has not been demonstrated so far. 

The pyrimidine antagonists inhibit the biosynthesis of pyrimidine nucleotides or interfere with vital cellular functions, such as the synthesis or function of nucleic acids. The analogues of deoxycytidine and thymidine that are used are inhibitors of DNA synthesis while 5-fluorouracil (5-FU) an analogue of uracil, is an inhibitor of both RNA function and of the synthesis of thymidylate (see Fig. 2). PALA (N-phosphonoacetyl-L-aspartate), an inhibitor of as-... 

Schroeder R, Waldsich C, Wank H (2000) Modulation of RNA function by aminoglycoside antibiotics. EMBOJ 19 1-9... 

Some RNAs Function Like Enzymes Some RNAs Are Self-Splicing Some Ribonucleases Are RNAs Ribosomal RNA Catalyzes Peptide Bond Formation Catalytic RNA May Have Evolutionary Significance Inhibitors of RNA Metabolism... 

Toulme, J.-J., Di Primo, C. and Moreau, S. (2001) Modulation of RNA function by oligonucleotides recognizing RNA structure. Progr. Nucleic Acid Res. Mol. Biol, (in press). 

Like other macromolecules, RNA is dynamic. The process of folding into a structured RNA involves dynamic rearrangement of RNA helices, and many RNAs function via a series of conformational transitions. Thus, measurement of the dynamics of individual helices will be required to fully understand RNA folding and function. Additionally, dynamic information can also be used to provide information about local structural features. 

Various kinds of RNA function in the production of proteins in living organisms. RNA also carries the genetic information in some viruses. There are many kinds of RNA, each with its own function. For example, messenger RNA, or mRNA, carries the information stored in the cell s DNA from the nucleus to other parts of the cell where it is used to make proteins. Another kind of RNA, transfer RNA, or tRNA, binds with amino acids and transfers them to where proteins are made. 

To take up the questions raised in this book, one would need to find papers with titles such as Twelve Intermediate Steps Leading to the Bacterial Photosynthetic Reaction Center, A Proto-Cilium Could Generate a Power Stroke Sufficient to Turn a Cell by Ten Degrees, Intermediates in Adenosine Biosynthesis Effectively Mimic Adenosine Itself in RNA Function, and A Primitive Clot Made of Randomly Aligned Fibers Would Block Circulation in Veins Smaller Than 0.3 Millimeters. But the papers are missing. Nothing remotely like this has been published. 

Antisense inhibition of RNA function requires the inhibition of thousands of copies of the target RNA present in the cell. However, inhibition of transcription at the level of DNA requires the inactivation of transcription from only one or two active copies of a gene present in the genome this is the rationale for... 

Geslain R, Ribas de Pouplana L. Regulation of RNA function by aminoacylation and editing Trends Genet. 2004 20 604-610. 

Grosjean H, ed. Fine-tuning of RNA Functions by Modification and Editing. 2005. Springer, Heidelberg. 

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