During each of the 4 larval stages in C. elegans development the renewal of the cuticle is controlled by the molting cycle. Coupled to the molting cycle is oscillatory gene expression of a large and diverse group of genes. It remains an open question whether these genes are only involved in molting or also play a role in other developmental processes. Interestingly, growth of the pharynx appears to have a cyclical character, indicating a potential link with the molting cycle. Here, we studied the interplay between pharynx-specific oscillatory genes and the growth of the pharynx. Using RNA-sequencing, single molecule FISH (smFISH) experiments and time-lapse imaging of transcriptional reporters, we identified a group of oscillatory genes that are expressed exclusively in the pharynx and peak at the early intermolt. These genes include
myo-1,
myo-2 and
marg-1, genes that likely play a structural role in pharynx muscle and marginal cells, respectively. Moreover, measuring size of the pharynx using time-lapse imaging of larval development revealed that pharyngeal growth was not constant, but, like expression of these genes, peaked at the early intermolt. We then used starvation-induced developmental arrest to perturb pharynx growth and examine the impact on oscillatory gene expression. In L1-arrested animals, both body and pharynx growth ceased simultaneously. In L3- or L4-arrested animals, however, pharynx growth continued for many hours after the arrest of body growth, until it reached a size corresponding to that seen at the time of the subsequent ecdysis during normal development. Consistently, in fully arrested animals we found that expression of oscillatory pharynx genes was halted at a phase corresponding to ecdysis. Moreover, in time-lapse imaging of transcriptional reporters we observed that continued pharynx growth after starvation-induced arrest of body growth is accompanied by one cycle of oscillatory gene expression. Overall, the observed coordination between the pharynx growth and expression oscillations of pharynx genes, both during normal development and following arrest, suggest that oscillating expression of these genes is functionally linked with organ growth.