Project description:Expression data from Caenorhabditis elegans let-418(RNAi), mep-1(RNAi) and gfp(RNAi) L1 larvae. The C. elegans genome encodes two homologs of the human protein Mi-2, namely LET-418 and CHD-3. LET-418 plays an essential role during development; its depletion leads to a pleiotropic and lethal phenotype that includes larval arrest, an everted vulva and sterility. Without maternal contribution, let-418 mutants stop their development at the L1 larval stage (von Zelewsky et al., 2000). We further characterized this arrest and showed that it is very similar to the L1 diapause induced by starvation; both germline and somatic cells remain in a quiescent state in let-418 L1 arrested larvae, indicating that LET-418 activity is required to bypass the L1 arrest in presence of food. The let-418 L1 larvae express ectopically the P granule component PGL-1 in somatic cells (Unhavaithaya et al., 2002). Interestingly, the phenotype of mep-1 mutants is remarkably similar to that of let-418: RNAi targeting mep-1 also induced an L1 arrest phenotype; furthermore, MEP-1 and LET-418 have been shown to physically interact (Unhavaithaya et al., 2002 and M. Passannante). The null allele mep-1(q660) is temperature sensitive and shows a more severe phenotype at higher temperatures. At 20°C, about 10% of mep-1 homozygotes derived from heterozygous mothers arrest as young larvae, whereas the remaining 90% develop into sterile adults (Belfiore et al., 2002). Later in development, the somatic gonad is affected in mep-1(q660) mutants. This results in an abnormal and disorganized gonad, a phenotype also observed in let-418(s1617) mutants. Both let-418 and mep-1 mutants produce a very limited number of oocytes and have pseudovulvae derived from P8.p (Belfiore et al., 2002; von Zelewsky et al., 2000 and C. Wicky, personal communication). Preliminary quantitative real-time PCR revealed that the expression of genes coding for P granule components was deregulated in both mep-1(RNAi) and let-418(RNAi) L1 larvae (data not shown). To further investigate this issue, we performed a complete gene expression analysis. Given the fact that mep-1(q660) mutants are sterile, we used RNA interference to generate mep-1 depleted worms. Bacteria expressing gfp dsRNA (pPE128.110 in HT115) were used as reference, since RNA interference may induce gene expression changes by itself. C. elegans L1 larvae treated with RNA interference were selected for RNA extraction and hybridization on Affymetrix microarrays. Synchronized wild type L4 animals were grown at 25° on bacteria expressing either gfp, let-418 or mep-1 dsRNA. Eggs were collected by bleaching gravid adults and allowed to hatch in the absence of food at 25°C. Newly hatched L1 larvae were fed on bacteria expressing the different dsRNA for three hours to recover from starvation. Three replicates per RNAi.
Project description:Expression data from Caenorhabditis elegans let-418(RNAi), mep-1(RNAi) and gfp(RNAi) L1 larvae. The C. elegans genome encodes two homologs of the human protein Mi-2, namely LET-418 and CHD-3. LET-418 plays an essential role during development; its depletion leads to a pleiotropic and lethal phenotype that includes larval arrest, an everted vulva and sterility. Without maternal contribution, let-418 mutants stop their development at the L1 larval stage (von Zelewsky et al., 2000). We further characterized this arrest and showed that it is very similar to the L1 diapause induced by starvation; both germline and somatic cells remain in a quiescent state in let-418 L1 arrested larvae, indicating that LET-418 activity is required to bypass the L1 arrest in presence of food. The let-418 L1 larvae express ectopically the P granule component PGL-1 in somatic cells (Unhavaithaya et al., 2002). Interestingly, the phenotype of mep-1 mutants is remarkably similar to that of let-418: RNAi targeting mep-1 also induced an L1 arrest phenotype; furthermore, MEP-1 and LET-418 have been shown to physically interact (Unhavaithaya et al., 2002 and M. Passannante). The null allele mep-1(q660) is temperature sensitive and shows a more severe phenotype at higher temperatures. At 20°C, about 10% of mep-1 homozygotes derived from heterozygous mothers arrest as young larvae, whereas the remaining 90% develop into sterile adults (Belfiore et al., 2002). Later in development, the somatic gonad is affected in mep-1(q660) mutants. This results in an abnormal and disorganized gonad, a phenotype also observed in let-418(s1617) mutants. Both let-418 and mep-1 mutants produce a very limited number of oocytes and have pseudovulvae derived from P8.p (Belfiore et al., 2002; von Zelewsky et al., 2000 and C. Wicky, personal communication). Preliminary quantitative real-time PCR revealed that the expression of genes coding for P granule components was deregulated in both mep-1(RNAi) and let-418(RNAi) L1 larvae (data not shown). To further investigate this issue, we performed a complete gene expression analysis. Given the fact that mep-1(q660) mutants are sterile, we used RNA interference to generate mep-1 depleted worms. Bacteria expressing gfp dsRNA (pPE128.110 in HT115) were used as reference, since RNA interference may induce gene expression changes by itself.
Project description:We characterized the effects of early-life starvation and reduced insulin/insulin-like signaling (IIS) during larval development on adult gene expression using mRNA-seq of whole worms. In our two-factor design, 'starved' worms were cultured without food (E. coli) in L1 arrest for eight days, and 'control' worms were starved overnight for synchronization. Both populations of worms were fed ad libitum with either empty vector (EV; negative control) or daf-2/InsR RNAi food (reduced IIS). RNAi was used rather than a daf-2 mutant so that the results would not be confounded by daf-2 function during L1 arrest, instead disrupting daf-2 only after starvation in fed, developing larvae. Upon reaching adulthood, animals were collected for transcript profiling.
Project description:Whole starved L1 larvae were collected with and without AMA-1 degradation by the auxin-inducible degron (AID) system in the soma and germ line between 36 and 132 hours of starvation along with controls.
Project description:Whole starved L1 larvae from four genotypes (N2, daf-2(e1370), irld-39(duk1);irld-52(duk17), and daf-2(e1370); irld-39(duk1); irld-52(duk17)) were collected after 12 hours of starvation
Project description:These are the 94 microarray experiments that are published in the paper: John Wang and Stuart K. Kim. Global analysis of dauer gene expression in Caenorhabditis elegans, Development 2003 130: 1621-1634. There are 94 individual microarray experiments divided into 3 broad experiments. The first experiment is a time course of dauer exit; each time course is labeled as "Dauer MTC#". The second experiment is a time course of L1 development after starvation arrest; each time couse is labeled "L1 MTC#". The final experiment is a comparison of pure dauers (0 hours) versus 12 hours after dauer exit and are labeled "Dauer Adjust". Every time course was repeated 4 times (#N)however for the dauer 4 and 7 hour time points there are only 3 replicates. For instance, all the time points labeled as "Dauer MTC#1" are from the same starting pool of dauer worms that were aliquoted into 10 fractions and analyzed at the time indicated. Every sample is compared to a common reference RNA that is used throughout all the hybridizations. In some cases there is a "-2" after the hour designation; this means the first hybridization failed for some technical reason and thus the second hybridization (same RNA) is reported.