Upon entering L1 diapause, RNA polymerase II quickly accumulates and pauses at promoter regions, and this accumulation was speculated to stop transcription and facilitate the immediate reinitiation of gene expression when food becomes available (2). Previous studies showed that the release of postdocking calcium-regulated dense-core vesicles, the insulin receptor (InsR) pathway, the AMPK pathway, and protein chaperones are required for the long-term survival of starved L1 worms (2–4). However, when newly hatched L1 worms encounter an environment with no food, developmental programs arrest and the worm enters L1 diapause. The presented results indicate that interactions between multiple miRNAs and likely a large number of their mRNA targets in multiple pathways regulate the response to starvation-induced L1 diapause. And we need to take seriously that, just as people’s literary diet matters, so does their ludic diet. In fact I still have a ton to say, about play anxiety and devaluation of play, which I’ll have to put into separate posts over the next few days.
These results suggest that a significant portion of the miR-71 activities in L1 diapause survival may be devoted to regulating the activities of UNC-31–mediated InsR/PI3K signaling and that the rest of miR-71 activity may regulate UNC-31–independent pathways. We next examined the relationship between miR-71 and UNC-31, which functions upstream of AGE-1 during L1 diapause by regulating calcium-regulated dense-core vesicle fusion and the release of an insulin-like ligand (3). Because the InsR pathway was previously shown to play a prominent role in L1 diapause (2, 3), we examined genetic interactions between miR-71 and different components of the InsR pathway. We identified 10 miRNA mutants that showed reduced survival rates with a stringent standard, as well as a few miRNA mutants with slightly increased survival rates (Table S1, Fig. 1D, and Fig. S1B). 1A because the ain-1 mutations reduce, but do not eliminate, miRISC functions.
- One who loves spending time with their family during the holidays and cooking delicious meals, despite the stress it sometimes brings on.
- These results indicate that miR-71 plays a significant role in larval development of animals recovering from L1 diapause and likely does so by regulating the expression of components of the insulin receptor/DAF-16 pathway, as well as factors acting downstream, or in parallel to, DAF-16.
- We speculate that the expression of heterochronic genes controlling the L2/L3 programs, including that of hbl-1 and lin-42, are increased during L1 diapause to arrest the developmental progression, and miR-71 is probably required to suppress these “excess” signals during the recovery phase (Fig. S5).
- The 8 months of “field research” that I engaged in after 1.5 years of sobriety in led me to the familiar line, “how did I get here (again)”.
- The nematode Caenorhabditis elegans responds to starvation by entering developmental arrest at multiple stages of its life cycle (1).
- However, the mechanisms that coordinate the long-term survival, overall developmental arrest, and reinitiation remain to be investigated.
In contrast, the mir-71(lf) mutant worms recovering on hbl-1(RNAi) displayed precocious VPC divisions similar to that seen in wild type (Fig. 4E). Consistent with the observation described above, the 4-d–starved mir-71(lf) mutants recovering on the RNAi control plates displayed the highly penetrant retarded defect in VPC division. (D) Bar graph showing that the delayed VPC timing defect of mir-71(lf) worms was enhanced by daf-16(lf) after 1 or 3 d of L1 starvation.