Doubletime (DBT), also known as discs overgrown (DCO), is a gene that encodes the doubletime protein in fruit flies (Drosophila melanogaster). Michael Young and his team at Rockefeller University first identified and characterized the gene in 1998.
The DBT-encoded protein is a kinase that phosphorylates the period (PER) protein, which is crucial in controlling the biological clock that regulates circadian rhythms.[1] Various mutations in the DBT gene have been observed to cause alterations in the period of locomotor activity in flies, including lengthening, shortening, or complete loss of the period in flies. In mammals, the homolog of DBT is casein kinase I epsilon, which has a similar role in regulating the circadian rhythm.
The circadian function of Drosophila and certain vertebrate Casein kinase 1 enzymes has been conserved over a long evolutionary timescale, making DBT and its homologs essential targets for research into the molecular mechanisms that underlie circadian rhythm regulation in various organisms.[2]