Sequences of Polymers
Jack Kyte in Structure in Protein Chemistry, 2006
Polymerases usually require a particular arrangement of double-helical nucleic acid. By direct chemical analysis of purified proteins, it has been shown that they are composed of linear polymers of amino acids, referred to as polypeptides. These polymers are formed by a ribosome that reads the messenger RNA and converts the sequence of codons into a sequence of amino acids coupled covalently together in the dictated order. The particular sequences of nucleotides and the associated points of cleavage are known as restriction sites, and the fragments of DNA produced by these cleavages are known as restriction fragments. Polypeptides are synthesized biologically by ribosomes that translate the sequence of nucleotides in a single-stranded messenger RNA into a sequence of amino acids in a polypeptide. A piece of DNA encoding another amino acid sequence is often inserted ahead of the DNA encoding the protein of interest.
The Molecular Basis of the Informational System–The Replication of DNA–The Trancription to mRNA– Protein Biosynthesis
Jean-Louis Burgot in Thermodynamics in Bioenergetics, 2019
This chapter begins by very briefly recalling the biosynthesis of informational macromolecules DNA and messenger RNA and, as a result, the building of proteins. Proteins are formed by condensation of amino acids. DNA is an extremely long chain, the links of which are located at four different recurring subunits, the mononucleotides. The information contained in DNA must first be transcribed to a chemical messenger. The latter is a ribonucleic acid named messenger RNA (mRNA). Messenger RNA has a chemical structure very similar to that of DNA. The complete mRNA diffuses into the cytoplasm from the nucleus and attaches to the ribosomes and the protein synthesis occurs on the surface of these ones. The protein biosynthesis is by far the most elaborate biosynthetic mechanism known. It is the reason why it seems interesting to us to mention very briefly its steps before finishing this book by considering the biological information.
RNA interference: a potential therapy for posterior pole diseases
A Peyman MD Gholam, A Meffert MD Stephen, D Conway MD FACS Mandi, Chiasson Trisha in Vitreoretinal Surgical Techniques, 2019
The cell accomplishes gene translation by producing messenger RNA (mRNA). The mRNA is then transcribed by ribosomes into an amino acid sequence that makes up peptides that are processed into proteins. mRNA provides the templates that the cell uses to manufacture proteins. Antisense and ribozymes were the first class of molecules to be created with the potential to target mRNA selectively and inhibit translation of the mRNA message. RNA interference is the silencing of gene production by activation of an innate cellular defense mechanism by double-stranded RNA. The potential therapeutic value of Small interfering RNA (siRNA) is tremendous, but many hurdles need to be overcome to achieve this potential. In systems other than the eye, siRNA has been able to alleviate disease processes by suppressing key gene products in the molecular pathway of the disease. Designing a siRNA against vascular endothelial growth factor (VEGF) requires screening siRNA molecules with sequences homologous to the VEGF gene.
The messenger's great message for vaccination
Published in Expert Review of Vaccines, 2015
Poly ribonucleic acid (RNA) is the only polymer capable to recapitulate all processes of life: containment of genetic information, enzymatic activities and capacity to create defined 3D structures. Since it has a remarkable chemical stability (at neutral or acidic pH) and can be modified to enhance/reduce particular features (e.g., stability in biological RNase containing milieus or recognition by immune sensors), it is a particularly versatile and ideal active pharmaceutical ingredient. However, the utilization of RNA as a gene vehicle (messenger RNA, mRNA) for therapy has only recently been exploited. Within this scope, mRNA-based vaccines designed to trigger anti-cancer, anti-virus or anti-allergy immune responses have been developed. Modifications of mRNA vectors and implementation of adequate formulations have allowed to turn this natural superlative biological molecule into a safe active pharmaceutical ingredient that can virtually address any medical need including vaccination or immunotherapy. This is the newest great message delivered by this messenger.
Osmolyte taurine induction in UVA exposed human retinal pigment epithelial cells
Published in Cutaneous and Ocular Toxicology, 2018
Aim: To explore the osmolytes expression in ultraviolet (UVA) stressed human retinal pigment epithelial cells. Methods: Osmolyte transporters and vascular endothelial growth factor (VEGF) messenger RNA (mRNA) were determined by real time polymerase chain reaction (PCR). Osmolyte uptake was measured by radioimmunoassay. VEGF concentrations were determined by immunoassay and enzyme-linked immunosorbent assay (ELISA). Osmolyte taurine transporter (TAUT) were silenced by siRNA technology. Results: Hypertonicity accelerated osmolyte betaine uptake, myoinositol uptake, and taurine uptake, compared to normotonic stress. UVA irradiation also accelerated osmolyte transporters expression and osmolytes uptake. Especially, osmolyte taurine remarkably inhibited VEGF release induced by UVA irradiation. VEGF in the UVA stressed retinal pigment epithelial cell supernatant was accumulated slow after taurine preincubation. VEGF expression increased significantly in UVA-stressed cells after TAUT silencing. Moreover, taurine reduced the VEGF level in human ocular aqueous humor. Conclusion: The inhibition of VEGF by osmolyte taurine plays the crucial role in retina adaption to UVA irradiation.
Serum metastasin mRNA is an important survival predictor in breast cancer
Published in British Journal of Biomedical Science, 2008
E. El-Abd, R. El-Tahan, L. Fahmy, S. Zaki, W. Faid, A. Sobhi, K. Kandil, F. El-Kwisky
This study investigates the possible prognostic role of serum metastasin messenger RNA (mRNA) in breast carcinoma as a non-invasive screening tool, and determines metastasin mRNA in the serum of breast cancer patients with high sensitivity (85%) and specificity (100%). A significant difference (P=0.05) was observed between serum metastasin mRNA and the number of involved lymph nodes. Patients with higher expression of serum metastasin showed poor survival (six times worse) than those with lower levels. Patients negative for serum metastasin mRNA suffered recurrences, while those positive for serum metastasin mRNA suffered distant metastases. The results of this study suggest that serum metastasin mRNA represents an important survival marker in breast carcinoma.
Related Knowledge Centers
- Rna
- Rna Splicing
- Transfer Rna
- Untranslated Rna
- Terminator Codon
- Spliceosomes
- Untranslated Regions