Shedding light on operons: Gene structure enabling the coregulation of structural genes

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This video sheds light on operons; a gene structural tool in prokaryotes and some eukaryotes, enabling the coordinated expression of several structural genes, which are usually functionally related! We show that the structure of operons is somewhat analogous to one light switch controlling many lightbulbs; operons consist of one common promoter (the light switch) and several structural genes (the lightbulbs), co-ordinately controlled. However, we show that the story is more complex as upstream of the promoter is an operator, a segment of DNA sensitive to a repressor of which is synthesised by another upstream regulatory gene.

To further bring light to this phenomenon and delve into the discovery of operons, the work of three remarkable scientists, Jacob, Sánchez and Monod, is explored. We highlight their pivotal work on the Lac operon in Escherichia coli K 12 in 1960. The three structural genes within the Lac operon are LacZ, LacY and LacA, giving rise to beta-galactosidase, galactoside permease and transacetylase, respectively. The scientists studied how different operator mutations altered lactose metabolism due to differential expression of certain Lac operon genes, beta-galactosidase and galactoside permease.

We also look at how many other scientists used this work as a springboard and were able to extend upon this knowledge base. From discovering whether the repressor molecule is RNA or protein, to the effect of allolactose on the system and potential activators of operons! This ground-breaking work won Jacob and Monod the Nobel Prize in 1965, however, the impact of their discoveries did not end here! The regulatory mechanisms in the Lac operon have been applied to a mouse model and in the future may be used for regulating reversible models of human disease!

Creator: Darcie Spina

References:
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