Circadian regulation of a viral gene promoter in live transgenic mice expressing firefly luciferase.
OBJECTIVE
This study was conducted to test for possible circadian control of viral infection in live animals using bioluminescence imaging of a firefly luciferase transgene.


METHODS
Transgenic mice expressing the firefly luciferase gene under the control of the promoter and enhancer of the human cytomegalovirus major immediate-early gene (CMV::luc) were examined through whole-animal imaging. Mice were crossed with HRS/J hairless albino mice to improve imaging of deep structures.


RESULTS
Transgene expression in the extremities and head was elevated around dusk in mice maintained in cycles of light and dark. Signal was also elevated during the animal's night in mice maintained in extended darkness. The viral promoter was induced during the active phase of the circadian locomotor rhythm in several tissues. Both the acinar cells and islets expressed the transgene in dissociated pancreas cultures.


CONCLUSIONS
These results suggest that viruses may exploit the circadian system for optimal timing of infection at particular phases in several tissue types.
Collaco
Anne M
AM
Department of Biological Sciences and the J.P. Scott Center for Neuroscience, Mind, and Behavior, Bowling Green State University, Bowling Green, OH, USA.
Rahman
Sima
S
Dougherty
Edward J
EJ
Williams
Brett B
BB
Geusz
Michael E
ME
D000818:Animals; D002940:Circadian Rhythm / Q000235:genetics*; D003587:Cytomegalovirus / Q000235:genetics; D015870:Gene Expression; D005814:Genes, Viral / Q000235:genetics*; D006801:Humans; D049409:Luciferases, Firefly / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D010179:Pancreas / Q000166:cytology / Q000201:enzymology; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012420:Running
D049409:Luciferases, Firefly