The Bridge between RNA and Protein- Translation and Protein Synthesis

Protein synthesis is a complicated process starting from the transcribing of mRNA from DNA, to the translation of mRNA into the peptide bond-chains. In Prokaryotes this process of transcription and translation can actually occur simultaneously, but in Eukaryotes they occur separately in different areas of the cell. In the figure we can see a visual example for the translation process.

A simplification of the translation process that showcases some of the multiple different RNAs and how the peptide chain grows in length.

In Eukaryotic organisms, there many different stages and versions of RNA. Through RNA we could find a way to modify protein synthesis in cells. One way is through animal microRNA- it was actually able to regulate gene expression. MicroRNAs are RNA regulators that control expression at the post-transcription level in Eukaryotes (Pillai 2007). Translation was actually restrained and as a result, hundreds of proteins from the genome were not produced (Selbach, 2008). We could possibly find a way to select what genes we want to be expressed through the manipulation of the RNA and how it regulates translation. We can see this type of research in influenza studies. Short interfering RNAs are shown to be able to hurt influenza virus production by attacking the RNAs of the virus, and not the RNA of the infected cell (Ge 2003).

The amount of information that can be contained in RNA is outstanding. Besides protein synthesis, there is even data that suggests the RNA may also hold information that codes for the death of the cell itself. Some neurons were found to die after becoming deprived of a growth factor, but when repressors were applied to the transcription/translation process, the cell continued to live and function well (Martin 1988). The fact that the cell had to produce proteins in order to die, supports the evidence that it’s own death was literally in the cell’s genetic code.

However, that same code contains processes that would protect the RNA from denaturation. In Eukaryotes, the RNA/DNA contains introns, “junk DNA,” that don’t code for anything. During the splicing process, where the junk DNA is cut out of the the RNA, if a mild heat shock is administered, the RNA will actually code for proteins that will protect the transcript process from heat that will denature the entire transcript, thus saving itself (Yost 1986).

Sources

Pillai, Ramesh S., Suvendra N. Bhattacharyya, and Witold Filipowicz. “Repression of Protein Synthesis by MiRNAs: How Many Mechanisms?”Trends in Cell Biology 17.3 (2007): 118-26.

Selbach, Matthias, Björn Schwanhäusser, Nadine Thierfelder, Zhuo Fang, Raya Khanin, and Nikolaus Rajewsky. “Widespread Changes in Protein Synthesis Induced by MicroRNAs.” Nature 455.7209 (2008): 58-63.

Ge, Q., M. T. Mcmanus, T. Nguyen, C.-H. Shen, P. A. Sharp, H. N. Eisen, and J. Chen. “RNA Interference of Influenza Virus Production by Directly Targeting MRNA for Degradation and Indirectly Inhibiting All Viral RNA Transcription.” Proceedings of the National Academy of Sciences 100.5 (2003): 2718-723.

Martin, D. P. “Inhibitors of Protein Synthesis and RNA Synthesis Prevent Neuronal Death Caused by Nerve Growth Factor Deprivation.” The Journal of Cell Biology 106.3 (1988): 829-44.

Yost, H.joseph, and Susan Lindquist. “RNA Splicing Is Interrupted by Heat Shock and Is Rescued by Heat Shock Protein Synthesis.” Cell 45.2 (1986): 185-93.