Messenger ribonucleic acid synthesis

Cellular protein biosynthesis involves the following steps. One strand of double-stranded DNA serves as a template strand for the synthesis of a complementary single-stranded messenger ribonucleic acid (mRNA) in a process called transcription. This mRNA in turn serves as a template to direct the synthesis of the protein in a process called translation. The codons of the mRNA are read sequentially by transfer RNA (tRNA) molecules, which bind specifically to the mRNA via triplets of nucleotides that are complementary to the particular codon, called an anticodon. Protein synthesis occurs on a ribosome, a complex consisting of more than 50 different proteins and several stmctural RNA molecules, which moves along the mRNA and mediates the binding of the tRNA molecules and the formation of the nascent peptide chain. The tRNA molecule carries an activated form of the specific amino acid to the ribosome where it is added to the end of the growing peptide chain. There is at least one tRNA for each amino acid. 

Meso-tetraaryl porphyrins, 14 552 Mesothelioma, 3 316 Messenger ribonucleic acid (mRNA), expression profiling and, 13 354 Messenger RNAs (mRNA), 12 449, 454, 473, 515 17 614, 627 20 824. See also mRNA synthesis... 

Ribosomal synthesis of peptides proceeds through translation of messenger ribonucleic acid (mRNA) and utilizes the 20 primary L-a-amino acids. These amino acids are incorporated with the use of specific transfer ribonucleic acid (tRNA) codons. The 20 primary a-amino acids, with the exception of glycine that is achiral, are characterized by an L-configuration at the a-position (Figure 1). In general, most proteins are found to be composed of these 20 L-a-amino acids, as such they are referred to as protein amino acids. 

All corticosteroids have the same general mechanism of action they traverse cell membranes and bind to a specific cytoplasmic receptor. The steroid-receptor complex translocates to the cell nucleus, where it attaches to nuclear binding sites and initiates synthesis of messenger ribonucleic acid (mRNA). The novel proteins that are formed may exert a variety of effects on cellular functions. The precise mechanisms whereby the corticosteroids exert their therapeutic benefit in asthma remain unclear, although the benefit is likely to be due to several actions rather than one specific action and is related to their ability to inhibit inflammatory processes. At the molecular level, corticosteroids regulate the transcription of a number of genes, including those for several cytokines. 

Chemical Synthesis and Biological Properties of the S -Terminus of Eukaryotic Messenger Ribonucleic Acids (mRNA)... 

Mauer RA (1982a) Thyroid hormone specifically inhibits prolactin synthesis and decreases prolactin messenger ribonucleic acid levels in cultured pituitary cells. Endocrinology 770 1507-1514. 

Mauer RA (1982b) Relationship between estradiol, ergocryptine, and thyroid hormone effects on prolactin synthesis and prolactin messenger ribonucleic acid levels. Endocrinology 770 1515-1520. 

Heme synthesis is controlled by a regulatory negative feedback loop in which heme inhibits the activity of fer-rochelatase and acquisition of iron fi om the transport protein transferrin. The decrease in iron acquisition leads to a decrease in iron uptake into the cell with subsequent decrease in 8-aminolevulinic acid and heme production. Iron deficiency and increased erythropoietin synthesis lead to the combination of the iron regulatory proteins with the iron-responsive elements in the transferrin receptor protein messenger ribonucleic acid (mRNA). This combination in turn leads to protection of the mRNA from degradation with subsequent increased uptake of iron into erythroid cells because of the increased expression of transferrin receptors on the cell membrane. 

Noll, H., Staehelin, T., and Wettstein, F. O., Ribosomal aggregate engaged in protein synthesis. Ergosome breakdown and messenger ribonucleic acid transport, Nature, 198, 632, 1963. 

Biopolymers are either synthesized by template-dependent or template-independent enzymatic processes. For the synthesis of nucleic acids and proteins a template is required, whereas all other polymers are synthesized by template-independent processes. The templates for nucleic acids are desoxyribonucleic acids or ribonucleic acids depending on the type of nucleic acid synthesized. For proteins, the template is messenger ribonucleic acid (mRNA). This has different impacts on the structure and on the molecular weights (MWs) of the polymers. Although both nucleic acids and proteins are copolymers with each type consisting of 4 or 22 different constituents, respectively, the distribution of the constituents is absolutely defined by the matrix and is not random. Furthermore, each representative of the two polymers has a defined MW. Polymers synthesized in template-dependent processes are monodisperse. All this is different in polymers synthesized by template-independent processes first of all, these polymers are polydisperse secondly, if these polymers are copolymers, the distribution of the constituents is more or less fully random. 

When not replicating, DNA serves as the code for synthesis of proteins. During protein synthesis, a small portion of DNA is copied by complementary base pairing of RNA nucleotides (adenine, guanine, cytosine and uracil instead of thymine) to form single stranded messenger ribonucleic acid (mRNA) in the nucleus of the cell. This process is known as transcription and is catalysed by an enzyme called RNA polymerase. 

Messenger Ribonucleic Acid (mRNA). Since DNA is found almost exclusively in the nucleus while protein synthesis occurs in the cytoplasm of the cell, a method must exist by which coding information contained in DNA is transmitted to the site of active protein formation. This messenger, a ribonucleic acid (mRNA), is single stranded. 

The coding instractions from the gene are transmitted by formation of a complementary single-strand intermediate messenger ribonucleic acid (mRNA), by a process called transcription. The mRNA migrates out of the nucleus into the cytoplasm, where it becomes the template for protein synthesis. 

Protein translation is the process of synthesizing proteins from amino acids. This series of reactions translates the code provided to messenger ribonucleic acid or RNA (mRNA) by deoxyribonucleic acid or DNA into a sequence of amino acids that makes up the active protein molecule. Protein synthesis begins with a strand of mRNA synthesized in response to the genetic code located in a gene on a strand of DNA. The process of translation is slightly different in eukaryotic cells from that in prokaryotic cells for the sake of simplicity, translation in prokaryotes will be discussed here. 

Contrary to the principles of the ribosomal protein biosynthesis, where the carboxylic functions of amino acids are reactively bound to a polymer — the transfer ribonucleic acid (t-RNA) — which itself is orientated specifically on the ribosomal messenger ribonucleic acid (m-RNA) (Fig. 1 for details see [36]), the basic idea of the Merrifield synthesis depends upon a nonreactive covalent fixation of the C-terminal amino acid of the target peptide on a solid support (Fig. 2). On this insoluble but swollen polymer, the pep-... 

Zalkin, H., Yanofsky C. and Squires, C. L. (1974) Regulated in vitro synthesis of Escherichia coli tryptophan operon messenger ribonucleic acid and enzymes. J. Biol. Chem. 249, 465. 

Gupta, S. L., Waterson, J., Sopori, M. L., Weissman, S. M. and Lengyel, P. (1971) Movement of the ribosome along the messenger ribonucleic acid during protein synthesis. Biochemistry, 10, 4410-4421. 

McKeehan, W. L., 1974, Regulation of hemoglobin synthesis Effect of concentration of messenger ribonucleic acid, ribosome subunits, initiation factors, and salts on ratio of a and p chains synthesized in vitro, J. Biol. Chem. 249 6517. 

Ennis, H. L. Protein synthesis and the inhibition of host messenger ribonucleic acid production in bacteriophage T4-infected Escherichia coli. Virology 40, 727-733 (1970). 

Sauerbier, W., Brautigam, a. R. Control of gene function in bacteriophage T4. II. Synthesis of messenger ribonucleic acid and protein after interrupting deoxyribonucleic acid replication and glucosylation. J. Virol. 5, 179-187 (1970). 

---