To test the hypothesis that these developmental timing revery play login genes mediate the regulatory role of miR-71 in larval development during recovery from starvation-induced L1 diapause, we examined whether knocking down HBL-1 function can suppress the retarded VPC timing defect of mir-71(lf). Reduction-of-function mutation (rf) in the age-1/PI3 kinase gene, age-1(hx546), made worms long-lived in the L1 starvation assay and was able to suppress the reduced L1 survival rate of mir-71(lf); the rate of the double mutants was comparable to that of wild type (Fig. 2A). Our genetic analysis indicated that for both L1 diapause survival and developmental recovery functions, miR-71 regulates expressions of genes in both the insulin receptor-dependent and -independent pathways.

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(D) Fractions of worms that carry 3′UTR reporter transgene and show no GFP expression GFP(−), weak GFP expression GFP(+/−), and comparable GFP expression to mCherry GFP(+). We found that the mRNA level of UNC-31 was up-regulated by about 20% in mir-71(lf) (Fig. 3A). 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.

miR-71 Is Not Required for Arresting Seam Cell or M-Cell Divisions During L1 Diapause.

To test whether the activity of the InsR pathway was down-regulated by miR-71, we first examined the endogenous expression of components of the InsR pathway in mir-71(lf). (C) The poor survival rate of daf-16(mu86, null) was enhanced by mir-71(lf). To identify individual miRNAs that play prominent roles in L1 diapause, we screened 72 available mutant strains of individual miRNAs and miRNA families (87 miRNAs in total) using the L1 starvation assay. (D) A representative chart of the L1 starvation survival rates of different miRNA mutants.
(B) Survival rate of single and double mutants to indicate the functional relationship between ain-1 and age-1. The two ain-1 loss-of-function alleles displayed significant reductions in L1 starvation survival rate. We further found that this survival rate reduction of ain-1 mutants was overcome by ectopic expression of the AIN-2 protein in the intestine but not in the muscle (Fig. 1A and Fig. S1A). We found that ain-1 but not ain-2 mutants displayed a significant reduction in L1 starvation survival rate compared with that of wild type (Fig. 1 A and D).

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• Images were pseudocolored in Photoshop CS3 (Adobe) and assembled in Illustrator CS3 (Adobe).
• Reduction-of-function mutation (rf) in the age-1/PI3 kinase gene, age-1(hx546), made worms long-lived in the L1 starvation assay and was able to suppress the reduced L1 survival rate of mir-71(lf); the rate of the double mutants was comparable to that of wild type (Fig. 2A).
• Compromising overall miRNA function dramatically reduces the survival rate of L1 worms in starvation-induced diapause, and the effect can be significantly suppressed by an age-1/PI3K mutation.
• We found that the 3′UTRs of several genes of the InsR pathway, including unc-31, age-1, pdk-1, akt-2, and sgk-1, contain predicted miR-71 targeting sites (as predicted by TargetScan and mirWIP).
• Duo Mobile’s restore functionality lets you back up Duo-protected accounts and third-party OTP accounts (such as Google or Facebook) for recovery to the same device or to a new device.
• Here we show that compromising overall microRNA (miRNA) functions or mutating certain individual miRNAs impairs the long-term survival of nematodes during starvation-induced L1 diapause.

On the other hand, the role of a particular miRNA (miR-71) is executed by repressing the expression of many genes in multiple pathways. On one hand, we showed that deletions of a good number of miRNAs have varying impacts on the L1 diapause survival rate, although they may effect the rate through different mechanisms. Instead, many specific physiological functions, such as the starvation-induced stress response, are regulated by a miRNA-target network, often involving multiple miRNAs and a large number of their targets. We found that the known developmental timing genes, hbl-1, lin-42, and lit-1, were at the top of the list (TargetScan). To understand how miR-71 affects VPC division, we searched its predicted targets for potential genes involved in regulating developmental timing. 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 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). 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. The overall effect of miRNAs on L1 starvation survival is expected to be significantly stronger than that reflected by the data in Fig.
Moreover, the expression of hbl-1 is repressed by let-7 family miRNAs at L3 during normal development, and the hyperactivity of hbl-1 caused by failure of miRNA regulation leads to retarded development (26). The reporter construct, the control plasmid, and a transformation marker plasmid were coinjected into worms to generate the extrachromosomal arrays for analysis. Elegans and Caenorhabditis briggsae, leading us to focus further analyses on these two genes. We further examined the functional relationship between miR-71 and DAF-16, a FOXO transcription factor acting critically and negatively downstream of AGE-1/PI3K in the InsR pathway.

Fig. 2.