Biology subjects

Ashley, G. E.

Publications and source records attributed to Ashley, G. E..

2 recordsLinked to original sources

bioRxiv2024

A conserved chronobiological complex times C. elegans development

The mammalian PAS-domain protein PERIOD (PER) and its C. elegans orthologue LIN-42 have been proposed to constitute an evolutionary link between two distinct, circadian and developmental, timing systems. However, while the function of PER in animal circadian rhythms is well understood molecularly and mechanistically, this is not true for LIN-42s function in timing rhythmic development. Here, using targeted deletions, we find that the LIN-42 PAS domains are dispensable for the proteins function in timing molts. Instead, we observe arrhythmic molts upon deletion of a distinct sequence element, conserved with PER. We show that this element, designated CK1{delta}-binding domain (CK1BD), mediates stable binding to KIN-20, the C. elegans CK1{delta}/{varepsilon} orthologue. We demonstrate that CK1{delta} phosphorylates LIN-42 and define two conserved helical motifs in the CK1BD, CK1BD-A and CK1BD-B, that have distinct roles in controlling CK1{delta}-binding and kinase activity in vitro. KIN-20 and the LIN-42 CK1BD are required for proper molting timing in vivo, and loss of LIN-42 binding changes KIN-20 subcellular localization. The interactions mirror the central role of a stable circadian PER-CK1 complex in setting a robust [~]24-hour period. Hence, our results establish LIN-42/PER - KIN-20/CK1{delta}/{varepsilon} as a functionally conserved signaling module of two distinct chronobiological systems.

developmental biology↗

bioRxiv2023

Regulation of the circadian clock in C. elegans by clock gene homologs kin-20 and lin-42

Circadian rhythms are endogenous oscillations present in nearly all organisms from prokaryotes to humans, allowing them to adapt to cyclical environments close to 24 hours. Circadian rhythms are regulated by a central clock, which is based on a transcription-translation feedback loop. One important protein in the central loop in metazoan clocks is PERIOD, which is regulated in part by Casein kinase 1{varepsilon}/{delta} (CK1{varepsilon}/{delta}) phosphorylation. In the nematode Caenorhabditis elegans, period and casein kinase 1{varepsilon}/{delta} are conserved as lin-42 and kin-20, respectively. Here we studied the involvement of lin-42 and kin-20 in circadian rhythms of the adult nematode using a bioluminescence-based circadian transcriptional reporter. We show that mutations of lin-42 and kin-20 generate a significantly longer endogenous period, suggesting a role for both genes in the nematode circadian clock, as in other organisms. These phenotypes can be partially rescued by overexpression of either gene under their native promoter. Both proteins are expressed in neurons and seam cells, a population of epidermal stem cells in C. elegans that undergo multiple divisions during development. Depletion of LIN-42 and KIN-20 specifically in neuronal cells after development was sufficient to lengthen the period of oscillating sur-5 expression. Therefore, we conclude that LIN-42 and KIN-20 are critical regulators of the adult nematode circadian clock through neuronal cells.

neuroscience↗