You probably already heard the concepts of translation in the central dogma of molecular biology. The dogma is an elucidation as to how a protein is born based on what the DNA holds. Based on it, the scheme begins at the DNA molecule being transcribed into RNA in a process called transcription, which is then followed by the RNA making a protein in a process called translation.
Crick’s central dogma: from transcription to translation
Francis Crick, the molecular biologist who was recognized together with James Watson as the first to formally reveal the helical structure of the DNA molecule in 1953, was also noted for his use of the term “central dogma”. He described the unidirectional flow of genetic information, i.e. from the transcription process to the translation process, and that the scheme does not entail reversion. Meaning, the scheme does not flow back from protein to DNA.
“The Central Dogma. This states that once ‘information’ has passed into protein it cannot get out again. In more detail, the transfer of information from nucleic acid to nucleic acid, or from nucleic acid to protein may be possible, but the transfer from protein to protein, or from protein to nucleic acid is impossible. Information means here the precise determination of sequence, either of bases in the nucleic acid or of amino acid residues in the protein.”1
— Francis Crick, 1958
The dogma is now succinctly known as this: DNA makes RNA, which in turn makes protein.
Real-time imaging of translation in vivo
In vivo transcription was the first to be quantified in real time whereas translation took a while before scientists were able to observe the process within a living cell. 2 It took them about 60 years from the time Francis Crick first described it. Translation is a process occurring in the cytoplasm of a cell by which the genetic code carried by the mRNA is decoded to produce the specific sequence of amino acids in a polypeptide chain. It consists of basically four stages: bioactivation, initiation, elongation, and termination. These translation processes had been more difficult to observe in living systems. Due to the limitations of laboratory tools and techniques it had eluded scientists for quite some time. Then, a team of researchers from the Colorado State University came up with state-of-the-art microscopic techniques, which helped them view for the first time the RNA translation in vivo. Fondly referred to as “Fixie”, the custom-built microscope helped the research team to create a real-time imaging of RNA translation within a living cell in a nanoscale precision.2 The research team was able to capture it firstly by using a tagging process by protein engineering and then using the “Fixie” microscope, which has two highly sensitive cameras enabling the imaging of RNA and proteins as two identifiable colors during the translation process.
In this video, it shows how a protein is being born. The red dots are RNA while the blue or green dots are the proteins. The large green spherical structure in the background is the cell nucleus. It can be seen that the mature proteins gather at the nucleus post-translation.
Real-time imaging of the translation of proteins by the RNA molecules can be regarded as a breakthrough. It can be likened to a key that opens the door to various research fields to explore. Proteins are crucial to the biomechanics of living things. They are the definitive goal of translation. Thus, research findings as fundamental as this is going to be irrefutably monumental.
— written by Maria Victoria Gonzaga
1 Crick, F.H.C. (1958). “On Protein Synthesis”. In F.K. Sanders. Symposia of the Society for Experimental Biology, Number XII: The Biological Replication of Macromolecules. Cambridge University Press. pp. 138–163.
2 Manning, A. (2016). No longer lost in translation: CSU biochemists watch gene expression in real time. Colorado State University. Retrieved from https://source.colostate.edu/no-longer-lost-in-translation-csu-biochemists-watch-gene-expression-in-real-time/