| dc.description.abstract | The circadian clock controls daily rhythms in messenger RNA (mRNA) accumulation of up to 40% of the eukaryotic genome. In addition, in the mouse liver, about 50% of proteins that cycle in abundance are produced from mRNAs that are constitutively expressed, indicating a role for the clock in the regulation of translation. While the basic mechanisms of circadian transcriptional control are known, little is understood about how the clock controls mRNA translation. We discovered that the clock in Neurospora crassa regulates the activity of eukaryotic elongation factor 2 (eEF2), a necessary component of translation elongation. These data suggested that clock regulation of protein abundance is dependent on rhythms in the activity of eEF2. To begin to test this idea, we used RNA-sequencing and ribosome profiling to determine which mRNAs and proteins cycle in abundance in N. crassa under control of the clock. For most genes, the peak ribosome occupancy of the mRNA coincided with the peak in mRNA levels. However consistent with clock regulation of translation, our preliminary data suggests that for some genes, rhythms in ribosome occupancy occurred on mRNAs that were constitutively expressed. My goal is to first validate the preliminary results for candidate genes that cycle only at the ribosome occupancy level, and then determine if the protein rhythms are dependent of clock control of eEF2 activity. | en |
