Figure 5. ISY-1 and ZIP-10 regulate a genetic program to promote organismic death.

(A) Venn diagram indicating numbers of genes commonly regulated by CW and isy-1(dma50) mutants. (B) Scatter plot depicting the correlation between the transcriptome response to cold (y-axis) and the transcriptome response to isy-1 mutation (x-axis). Shown are the log2 fold changes compared with corresponding controls. Pearson correlation coefficient and the associated P-value were calculated using R functions. (C) AT-rich motif identified by MEME enriched among the CW and isy-1(dma50) regulated genes, with a table listing numbers of the motif present in top-ranked four genes. (D) ChIP-QPCR measurements of ZIP-10::FLAG binding to the asp-17 promoter. (E) Survival rates of indicated genotypes after prolonged CW (4°C for 48 hrs followed by 4 hrs of warming). (F) Organismic death rates of indicated genotypes after heat shock (32°C) induction of zip-10 wild type, mutant with defective transactivation C-terminus, zip-2 and zip-11 (left), without CW. Nomarski image (right) indicates morphologies of normal and dead animals with induction of zip-10. (G) RNA-seq measurements of gene targets of indicated TFs. (H) Table showing the asp-17p::GFP and cold tolerance phenotypes of animals with indicated genotypes. (I) Model for the role and regulation of the ZIP-10 pathway. n ≥ 20 total animals for each group with N ≥ 3 independent biological replicates; *** indicates p<0.001.

Figure 5—figure supplement 1. Identification of differentially regulated microRNAs in wild type and isy-1(dma50) mutants.

(A) Summary table showing the read statistics for the small RNA-seq experiments using three biologically triplicate samples in wild type and isy-1(dma50) mutants. (B) Small RNA length distribution plots for wild type and isy-1(dma50) mutants. (C) Distribution graphs for various types of small RNAs identified by small RNA sequencing for wild type and isy-1(dma50) mutants. (D) Volcano plot showing the differentially regulated microRNAs, including mir-60, in the isy-1(dma50) mutants (three replicates each). (E) Schematic of two examples illustrating the TF-encoding genes, skn-1 and daf-16 at 3’ UTRs, targeted by two microRNAs, mir-51 and mir-359, respectively, which are down-regulated in isy-1(dma50) mutants. (F) Hierarchical clustering analysis of microRNAs up- or down-regulated in isy-1(dma50) mutants. mir-51 and mir-359 down-regulation were indicated by arrows.

Figure 5—figure supplement 2. ZIP-10 constitutes a genetic program promoting kin selection of C. elegans under resource-limiting and stress conditions.

(A) Mathematical model illustrating the advantage of wild-type (red line) versus zip-10 KO animals (blue line) at the population level under growth resource-liming and thermal stress conditions. Individual fitness distribution (x-axis) after cold-warming thermal stress is set to be exponential (thin red line) and linear (thin blue line) to fit the phenotypic differences in death rates of wild type and zip-10 KO animals and to simplify comparison and calculation. Given the same period of time and the same amount of growth resources (integral differences between thin and thick lines), wild-type population yields more thermal stress-adapted reproducing animals than zip-10 deficient animals. The parameters for integrals were adjusted so that the ‘growth resources’ are the same despite that the population growth modes are different for wild type and zip-10 KO. (B) Schematic illustrating an exemplar situation of the mathematical model in which five post-reproduction adults and five larvae are living in a food-limiting condition. After cold-warming thermal stress, wild-type adults die out, leaving food for young larvae to grow into reproductive adults whereas zip-10 KO post-reproduction adults do not die, consuming the limited food and competing out the young larvae so that fewer reproductively active zip-10 KO animals emerge from such conditions. (C) Experimental evidence indicating the specific induction of zip-10p::zip-10::EGFP::FLAG by CW as measured by western blot in adults but not in larvae. (D) Survival rates of wild type and zip-10 KO (ok3462) animals at different stages after prolonged CW thermal stresses (96 hrs cold shock for L1 while 48 hrs for others) showing that ZIP-10’s pro-death effects are more prominent in old animals. n ≥ 20 total animals for each group with N ≥ 3 independent biological replicates; *** indicates p<0.001, ** indicates p<0.01.