Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
2801936 | General and Comparative Endocrinology | 2007 | 4 Pages |
Cryptochromes (Cry) are core components in the gene regulation of circadian rhythmic processes. It was shown earlier, that Cry1 mRNA content of the avian pineal gland was increased after a 4 h exposure to light during subjective night; however, a 30 min exposure was ineffective. In this study, changes in pineal Cry1 expression were detected in chickens during and after being placed into reversed light/dark environment. Cry1 mRNA content was higher if light was on during the night; however, in the first 2 h of light exposure at night, Cry1 mRNA contents were decreased. Following the first overnight light exposure, the peak of the mRNA expression was delayed for 12 h compared to controls. Our results suggest that environmental illumination activates a complex regulatory cascade that includes both up- and down-regulation of the Cry1 gene which inverses the 24 h pattern of Cry1 mRNA expression within one period.