Biochemistry of cell gene expression (Introduction)

by David Turell @, Tuesday, January 08, 2019, 23:58 (11 days ago) @ David Turell

Obviously cells have to control their gene expresson so it stays within proper limits:

"The findings, first reported on bioRxiv, could ultimately improve our understanding of how certain antibacterial drugs work against the enzyme RNA polymerase (RNAP) in treating conditions such as Clostridium difficile infections and tuberculosis.

"Gene expression occurs when the information contained in DNA is used to produce functional gene products such as proteins and other molecules. The process has two stages. In the first stage, called transcription, RNAP reads the information in a strand on DNA, which is then copied into a new molecule of messenger ribonucleic acid (mRNA). In the second stage, the molecule then moves on to be processed or translated.

"However, to help control gene expression levels, transcriptional pausing by RNAP can occur between the two stages, providing a kind of 'roadblock' where transcription may be terminated or modulated.

"'A consensus pause sequence that acts on RNAPs in all organisms, from bacteria to mammals, halts the enzyme in an elemental paused state from which longer-lived pauses can arise," explains senior author Robert Landick,


"The team's analyses first revealed that the elemental pause process involves several biological players, which together create a barrier to prevent escape from paused states. The process also causes a modest conformational shift that makes RNAP 'stumble' in feeding DNA into its reaction centre, temporarily stopping it from making RNA.

"'We also found that transcriptional pausing makes RNAP loosen its grip and backtrack on the DNA while paused," says Landick. "Together, these results provide a framework to understand how the process is controlled by certain conditions and regulators within cells.'"

Comment: Cells which are high speed production factories and must have tight controls over outputs that are made to stay within required limits. Cells make split-second decisions based on tight controls by 'regulators'. This is all automatic molecular activity. It must be to work at such constant high speed. Only cellular design can achieve this homeostasis, and homeostasis is what creates the phenomenon of living matter. The universe has homeostasis in its organization, but it is equal to living matter.

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