Although the role of each gene is slightly different, this animation features one Per and one Cry gene for clarity. Transcriptional activation results in the production of mRNA, which exits the nucleus through nuclear pores and is translated into protein by the ribosomes. A dimer is a pair of molecules. Over time, the dimers degrade and are replaced by other dimers. Eventually, too few dimers are available to block activation because no more proteins are being made.
Inhibition is relieved, and transcriptional activation begins again.
Please click on Part 2 to view the next level of complexity in the molecular model.