5 As redes hiperb´olicas os transientes
5.2 A taxa de escape
Many additional questions remain regarding how DAF-18/PTEN maintains quiescence in, and coordinates it between, the somatic gonad and germline in dauer. The mechanism by which the somatic gonad signals both inter se and to the germline to maintain quiescence is intriguing and unanswered, if partially characterized. Another captivating question is how somatic gonad and germline arrest is coordinated with that of non-gonadal tissues in dauer, and whether the decision to enter dauer is relayed through the somatic gonad to the germline rather than directly to both tissues from external sources. Other questions include:
Does DAF-9-mediated dafachronic acid signaling support progression differentially between the somatic gonad and germline? Does this progression require daf-12?
Do canonical dauer entry pathways regulate somatic gonad quiescence upstream of the somatic gonad-derived signal?
How does DAF-18/PTEN activity prevent cellular fate specification and differentiation in the SGB descendants? Is daf-18 also required to prevent differentiation of the GSCs in dauer? What causes the abnormalities seen in somatic gonad and germline morphology in daf-18(0) dauers, and is the observed loss of quiescence controlled or uncontrolled proliferation?
What role, if any, does daf-16/FoxO play in preventing fate specification in the somatic gonad in dauer? Is LIN-12/Notch signaling blocked in the dauer VUs, and if so, does this block require daf-16/FoxO as in the VPCs? Is the low-penetrance loss of quiescence observed in the VUs of daf-16(0) dauers a result of LIN-12/Notch activation?
Figure 1. Tissue-specific expression of daf-18(+) in the somatic gonad rescues somatic gonad and germline quiescence in dauer. All strains have daf-7(e1372) and markers (A) Expression pattern of the ckb-3, hlh-12, and hlh-2prox promoters are indicated in the somatic gonad primordium. ckb-3(784)p is expressed in the somatic gonad precursors Z1 and Z4 (Kroetz and Zarkower, 2015) and in all of their descendants in the somatic gonad primordium during dauer (described in Chapter 2). hlh-12(1080)p expression is restricted to the DTCs in continuous development from L2 onwards (Tamai and Nishiwaki, 2007) and was also visible only in the DTCs in daf-7(e1372); daf-18(ok480) arIs51[cdh-3::gfp]; arEx2416[hlh-12(1080)p::daf-
18::T2A::tagBFP2::unc-54 3’UTR] dauers (futher details in Chapter 2). hlh-2prox is a fragment
of the hlh-2 promoter expressed in the four cells that become the AC and VUs (Sallee and Greenwald, 2015) and is expressed in the AC in dauer (personal communication from Catherine O’Keeffe). (B) daf-7(e1372); daf-18(ok480) arIs51[cdh-3::gfp] dauers were scored for somatic gonad development in dauer if cdh-3::gfp expression was seen in the uste of the somatic gonad. With rare exceptions, individuals in which somatic gonad developmental arrest was rescued by
daf-18(+) constructs also maintained germline arrest as assessed by Nomarski differential
interference contrast. Single-copy transgenes expressing daf-18cDNA::T2A::tagBFP2::unc-54
3’UTR under the hlh-12, ckb-3, or hlh-2prox promoters were generated by miniMos insertion
(Frøkjær-Jensen et al., 2014), with two independent insertion lines scored for hlh-2prox. A viral 2A peptide, T2A, triggers “ribosomal pausing” such that a single transcript produces two
independent proteins (here DAF-18 and tagBFP2) (Ahier and Jarriault, 2014). n = 22-37. (***) P ckb-3p: Z1, Z4 & descendants hlh-12p: DTCs hlh-2prox: AC & VUs Z1 DTC Z4 DTC VU VU VU AC 0% 50% 100% arTi111[hlh-2prox::daf-18] arTi107[hlh2-prox::daf-18] arTi118[hlh-12p::daf-18] arTi195[ckb-3p::daf-18] daf-18(0) Control SGB progression
(cdh-3::gfp utse expression utse in dauer)
cdh-3::gfp+ utse daf-18(0)
***
NS NS***
1A
1B
Figure 2. The somatic gonad primordium envelops both germline arms in dauer. Expression of the somatic gonad marker ckb-3p::mCherry in the dauer somatic gonad. Top, Nomarksi
differential interference contrast (DIC) merge with mCherry; bottom, mCherry fluorescent expression. Pictures show the entire somatic gonad and germline region of the dauer. The center of the “bowtie” pattern of fluorescence is expression in the proximal somatic gonad, with extended expression around each germline arm from DTCs and SS precursors (no expression is visible in the germline, as expected). Expression shown is from arEx2418[ckb-3p::mCherry::unc- 54 3’UTR] in starved dauers selected by morphological criteria including presence of dauer alae,
radial constriction, and pharyngeal constriction. Identical expression pattern was observed in 7/7 dauers examined. Strain is GS8215 and was incubated at 25˚C for this experiment.
Figure 3. In dauers, the transgene qIs90[ceh-22b::yfp] is brightly expressed in the DTCs (Z1.aa and Z4.pp) and the two SS cells that are DTC lineal sisters (Z1.ap and Z4.pa). This pattern is consistent with the reported expression pattern in continuous development L2 larvae (Lam et al., 2006). Dim expression is also visible in other cells of the somatic gonad primordium, consistent with published observations that this transgene is expressed in Z1 and Z4 in the L1 and becomes primarily restricted to the DTC and DTC sisters by L2 (Lam et al., 2006). This expression pattern was observed in 23/23 qIs90[ceh-22b::yfp]; daf-7(e1372) dauers isolated by SDS selection after incubation from eggs at 25˚C for 72 hours (1-day dauers).
References
Adhikari, D., Zheng, W., Shen, Y., Gorre, N., Hamalainen, T., Cooney, A.J., Huhtaniemi, I., Lan, Z.-J., and Liu, K. (2010). Tsc/mTORC1 signaling in oocytes governs the quiescence and activation of primordial follicles. Hum. Mol. Genet. 19, 397–410.
Ahier, A., and Jarriault, S. (2014). Simultaneous expression of multiple proteins under a single promoter in Caenorhabditis elegans via a versatile 2A-based toolkit. Genetics 196, 605–613. Albert, P.S., and Riddle, D.L. (1988). Mutants of Caenorhabditis elegans that form dauer-like larvae. Dev. Biol. 126, 270–293.
Alimonti, A., Carracedo, A., Clohessy, J.G., Trotman, L.C., Nardella, C., Egia, A., Salmena, L., Sampieri, K., Haveman, W.J., Brogi, E., et al. (2010). Subtle variations in Pten dose determine cancer susceptibility. Nat. Genet. 42, 454–458.
Antebi, A. (2006). Nuclear hormone receptors in C. elegans. WormBook 1–13.
Antebi, A. (2013). Steroid regulation of C. elegans diapause, developmental timing, and longevity. (Elsevier Inc.).
Antebi, A. (2015). Nuclear receptor signal transduction in C. elegans. WormBook 1–49.
Antebi, A., Culotti, J.G., and Hedgecock, E.M. (1998). daf-12 regulates developmental age and the dauer alternative in Caenorhabditis elegans. Development 125, 1191–1205.
Antebi, A., Yeh, W.H., Tait, D., Hedgecock, E.M., and Riddle, D.L. (2000). daf-12 encodes a nuclear receptor that regulates the dauer diapause and developmental age in C. elegans. Genes Dev. 14, 1512–1527.
Armenti, S.T., Lohmer, L.L., Sherwood, D.R., and Nance, J. (2014). Repurposing an endogenous degradation system for rapid and targeted depletion of C. elegans proteins. Development 141, 4640–4647.
Ashton, F.T., Li, J., and Schad, G.A. (1999). Chemo- and thermosensory neurons: Structure and function in animal parasitic nematodes. Vet. Parasitol. 84, 297–316.
Austin, J., and Kimble, J. (1987). glp-1 Is required in the germ line for regulation of the decision between mitosis and meiosis in C. elegans. Cell 51, 589–599.
Baugh, L.R., and Sternberg, P.W. (2006). DAF-16/FOXO Regulates Transcription of cki- 1/Cip/Kip and Repression of lin-4 during C. elegans L1 Arrest. Curr. Biol. 16, 780–785. Beer, K.B., and Wehman, A.M. (2017). Mechanisms and functions of extracellular vesicle release in vivo-What we can learn from flies and worms. Cell Adh Migr 11, 135–150.
Brenner, S. (1974). THE GENETICS OF CAENORHABDITIS ELEGANS. Genetics 77. Brisbin, S., Liu, J., Boudreau, J., Peng, J., Evangelista, M., and Chin-Sang, I. (2009). A Role for C. elegans Eph RTK Signaling in PTEN Regulation. Dev. Cell 17, 459–469.
Burdine, R.D., Branda, C.S., and Stern, M.J. (1998). EGL-17(FGF) expression coordinates the attraction of the migrating sex myoblasts with vulval induction in C. elegans. Development 125, 1083–1093.
Burgering, B.M.T., and Medema, R.H. (2003). Decisions on life and death: FOXO Forkhead transcription factors are in command when PKB/Akt is off duty. J. Leukoc. Biol. 73, 689–701. Butcher, R.A., Fujita, M., Schroeder, F.C., and Clardy, J. (2007). Small-molecule pheromones that control dauer development in Caenorhabditis elegans. Nat. Chem. Biol. 3, 420–422.
Butcher, R.A., Ragains, J.R., Li, W., Ruvkun, G., Clardy, J., and Mak, H.Y. (2009). Biosynthesis of the Caenorhabditis elegans dauer pheromone. Proc. Natl. Acad. Sci. U. S. A. 106, 1875–1879. Cantley, L.C., and Neel, B.G. (1999). New insights into tumor suppression: PTEN suppresses tumor formation by restraining the phosphoinositide 3-kinase/AKT pathway. Proc. Natl. Acad. Sci. U. S. A. 96, 4240–4245.
Cassada, R.C., and Russell, R.L. (1975). The Dauerlarva , a Post-Embryonic Nematode Developmental elegans Variant of the Caenorhabditis. 342, 326–342.
Chang, C., Newman, A.P., and Sternberg, P.W. (1999). Reciprocal EGF signaling back to the uterus from the induced C. elegans vulva coordinates morphogenesis of epithelia. Curr. Biol. 9, 237–246.
Chen, N., and Greenwald, I. (2004). The lateral signal for LIN-12/Notch in C. elegans vulval development comprises redundant secreted and transmembrane DSL proteins. Dev. Cell 6, 183– 192.
Cheung, T.H., and Rando, T.A. (2013). Molecular regulation of stem cell quiescence. Nat. Rev. Mol. Cell Biol. 14, 329–340.
Chiang, W.-C., Ching, T.-T., Lee, H.C., Mousigian, C., and Hsu, A.-L. (2012). HSF-1 regulators DDL-1/2 link insulin-like signaling to heat-shock responses and modulation of longevity. Cell
148, 322–334.
Choi, M.S. (2009). Genes that act in specification of the vulval secondary fate in Caenorhabditis elegans. 262.
Cinar, H.N., Richards, K.L., Oommen, K.S., and Newman, A.P. (2003). The EGL-13 SOX domain transcription factor affects the uterine pi cell lineages in Caenorhabditis elegans. Genetics 165, 1623–1628.
for sensory development and function in C. elegans. Neuron 17, 695–706.
Coburn, C.M., Mori, I., Ohshima, Y., and Bargmann, C.I. (1998). A cyclic nucleotide-gated channel inhibits sensory axon outgrowth in larval and adult Caenorhabditis elegans: a distinct pathway for maintenance of sensory axon structure. Development 125, 249–258.
Colella, E., Li, S., and Roy, R. (2016). Developmental and Cell Cycle Quiescence Is Mediated by the Nuclear Hormone Receptor Coregulator DIN-1S in the Caenorhabditis elegans Dauer Larva. Genetics 203, 1763–1776.
Cornils, A., Gloeck, M., Chen, Z., Zhang, Y., and Alcedo, J. (2011). Specific insulin-like
peptides encode sensory information to regulate distinct developmental processes. Development
138, 1183–1193.
Dalfó, D., Michaelson, D., and Hubbard, E.J.A. (2012). Sensory Regulation of the C. elegans Germline through TGF-$β$-Dependent Signaling in the Niche. Curr. Biol. 22, 712–719. Dijkers, P.F., Medema, R.H., Pals, C., Banerji, L., Thomas, N.S., Lam, E.W., Burgering, B.M., Raaijmakers, J.A., Lammers, J.W., Koenderman, L., et al. (2000). Forkhead transcription factor FKHR-L1 modulates cytokine-dependent transcriptional regulation of p27(KIP1). Mol. Cell. Biol. 20, 9138–9148.
Dixon, S.J., Alexander, M., Chan, K.K.M., and Roy, P.J. (2008). Insulin-like signaling negatively regulates muscle arm extension through DAF-12 in Caenorhabditis elegans. Dev. Biol. 318, 153–161.
Eijkelenboom, A., and Burgering, B.M.T. (2013). FOXOs: signalling integrators for homeostasis maintenance. Nat. Rev. Mol. Cell Biol. 14, 83–97.
Escoté, X., and Fajas, L. (2015). Metabolic adaptation to cancer growth: From the cell to the organism. Cancer Lett. 356, 171–175.
Euling, S., and Ambros, V. (1996). Reversal of cell fate determination in Caenorhabditis elegans vulval development. Development 122, 2507–2515.
Feinberg, E.H., and Hunter, C.P. (2003). Transport of dsRNA into Cells by the Transmembrane Protein SID-1. Science (80-. ). 301, 1545–1547.
Feliciano, D.M., Zhang, S., Nasrallah, C.M., Lisgo, S.N., and Bordey, A. (2014). Embryonic Cerebrospinal Fluid Nanovesicles Carry Evolutionarily Conserved Molecules and Promote Neural Stem Cell Amplification. PLoS One 9, e88810.
Ferguson, E.L., and Horvitz, H.R. (1985). IDENTIFICATION AND CHARACTERIZATION OF 22 GENES THAT AFFECT THE VULVAL CELL LINEAGES OF THE NEMATODE CAENORHABDITIS ELEGANS. Genetics 110.
Fernandes de Abreu, D.A., Caballero, A., Fardel, P., Stroustrup, N., Chen, Z., Lee, K., Keyes, W.D., Nash, Z.M., Lopez-Moyado, I.F., Vaggi, F., et al. (2014). An insulin-to-insulin regulatory network orchestrates phenotypic specificity in development and physiology. PLoS Genet 10, e1004225.
Fielenbach, N., and Antebi, A. (2008). C. elegans dauer formation and the molecular basis of plasticity. Genes Dev. 22, 2149–2165.
Fiore, A.P.Z.P., Ribeiro, P. de F., and Bruni-Cardoso, A. (2018). Sleeping Beauty and the Microenvironment Enchantment: Microenvironmental Regulation of the Proliferation-
Quiescence Decision in Normal Tissues and in Cancer Development. Front. Cell Dev. Biol. 6, 59.
Fire, A., Harrison, S.W., and Dixon, D. (1990). A modular set of lacZ fusion vectors for studying gene expression in Caenorhabditis elegans. Gene 93, 189–198.
Frøkjær-Jensen, C., Davis, M.W., Sarov, M., Taylor, J., Flibotte, S., LaBella, M., Pozniakovsky, A., Moerman, D.G., and Jorgensen, E.M. (2014). Random and targeted transgene insertion in Caenorhabditis elegans using a modified Mos1 transposon. Nat. Methods 11, 529–534. Fukushige, T., Brodigan, T.M., Schriefer, L.A., Waterston, R.H., and Krause, M. (2006). Defining the transcriptional redundancy of early bodywall muscle development in C. elegans: evidence for a unified theory of animal muscle development. Genes Dev 20, 3395–3406. Fukuyama, M., Gendreau, S.B., Derry, W.B., and Rothman, J.H. (2003). Essential embryonic roles of the CKI-1 cyclin-dependent kinase inhibitor in cell-cycle exit and morphogenesis in C. elegans. Dev. Biol. 260, 273–286.
Fukuyama, M., Rougvie, A.E., and Rothman, J.H. (2006). C. elegans DAF-18/PTEN Mediates Nutrient-Dependent Arrest of Cell Cycle and Growth in the Germline. Curr. Biol. 16, 773–779. Fukuyama, M., Sakuma, K., Park, R., Kasuga, H., Nagaya, R., Atsumi, Y., Shimomura, Y., Takahashi, S., Kajiho, H., Rougvie, A., et al. (2012). C. elegans AMPKs promote survival and arrest germline development during nutrient stress. Biol. Open 1, 929–936.
Fukuyama, M., Kontani, K., Katada, T., and Rougvie, A.E. (2015). The C. Elegans hypodermis couples progenitor cell quiescence to the dietary state. Curr. Biol. 25, 1241–1248.
Gabriel, K., Ingram, A., Austin, R., Kapoor, A., Tang, D., Majeed, F., Qureshi, T., and Al-
Nedawi, K. (2013). Regulation of the Tumor Suppressor PTEN through Exosomes: A Diagnostic Potential for Prostate Cancer. PLoS One 8, e70047.
Gerisch, B., Antebi, A. (2004). Hormonal signals produced by DAF-9/cytochrome P450 regulate C. elegans dauer diapause in response to environmental cues. Development 131, 1765–1776. Gerisch, B., Weitzel, C., Kober-Eisermann, C., Rottiers, V., and Antebi, A. (2001). A Hormonal Signaling Pathway Influencing C. elegans Metabolism, Reproductive Development, and Life
Gerisch, B., Antebi, A., and Riddle, D.L. (2004). Hormonal signals produced by DAF- 9/cytochrome P450 regulate C. elegans dauer diapause in response to environmental cues. Development 131, 1765–1776.
Ghosh, S., and Sternberg, P.W. (2014). Spatial and molecular cues for cell outgrowth during C. elegans uterine development. Dev. Biol. 396, 121–135.
Gil, E.B., Malone Link, E., Liu, L.X., Johnson, C.D., and Lees, J.A. (1999). Regulation of the insulin-like developmental pathway of Caenorhabditis elegans by a homolog of the PTEN tumor suppressor gene. Proc. Natl. Acad. Sci. U. S. A. 96, 2925–2930.
Gottlieb, S., and Ruvkun, G. (1994). daf-2, daf-16 and daf-23: genetically interacting genes controlling Dauer formation in Caenorhabditis elegans. Genetics 137, 107–120.
Greenwald, I. (2012). Notch and the awesome power of genetics. Genetics 191, 655–669. Greenwald, I., and Kovall, R. (2013). Notch signaling: genetics and structure. WormBook 1–28. Greenwald, I.S., Sternberg, P.W., and Robert Horvitz, H. (1983). The lin-12 locus specifies cell fates in caenorhabditis elegans. Cell 34, 435–444.
Gumienny, T.L., and Savage-Dunn, C. (2013). TGF-β signaling in C. elegans. WormBook 1–34. Gupta, B.P., and Sternberg, P.W. (2002). Tissue-specific regulation of the LIM homeobox gene lin-11 during development of the Caenorhabditis elegans egg-laying system. Dev Biol 247, 102– 115.
Gupta, B.P., Wang, M., and Sternberg, P.W. (2003). The C. elegans LIM homeobox gene lin-11 specifies multiple cell fates during vulval development. Development 130, 2589–2601.
Hall, S.E., Beverly, M., Russ, C., Nusbaum, C., and Sengupta, P. (2010). A Cellular Memory of Developmental History Generates Phenotypic Diversity in C. elegans. Curr. Biol. 20, 149–155. Hanna-Rose, W., and Han, M. (1999). COG-2, a sox domain protein necessary for establishing a functional vulval-uterine connection in Caenorhabditis elegans. Development 126, 169–179. Herman, R.K. (1984). Analysis of genetic mosaics of the nematode Caneorhabditis elegans. Genetics 108, 165–180.
Hermann, G.J., Schroeder, L.K., Hieb, C.A., Kershner, A.M., Rabbitts, B.M., Fonarev, P., Grant, B.D., and Priess, J.R. (2005). Genetic analysis of lysosomal trafficking in Caenorhabditis
elegans. Mol Biol Cell 16, 3273–3288.
Hoier, E.F., Mohler, W.A., Kim, S.K., and Hajnal, A. (2000). The Caenorhabditis elegans APC- related gene apr-1 is required for epithelial cell migration and Hox gene expression. Genes Dev
kinase inhibitor controls postembryonic cell cycle progression in Caenorhabditis elegans. Development 125, 3585–3597.
Hopkins, B.D., Fine, B., Steinbach, N., Dendy, M., Rapp, Z., Shaw, J., Pappas, K., Yu, J.S., Hodakoski, C., Mense, S., et al. (2013). A secreted PTEN phosphatase that enters cells to alter signaling and survival. Science (80-. ). 341, 399–402.
Hopkins, B.D., Hodakoski, C., Barrows, D., Mense, S.M., and Parsons, R.E. (2014). PTEN function: the long and the short of it. Trends Biochem. Sci. 39, 183–190.
Hu, P.J. (2007). Dauer. WormBook.
Huang, H., Potter, C.J., Tao, W., Li, D., Brogiolo, W., Hafen, E., Sun, H., and Xu, T. (1999). PTEN affects cell size, cell proliferation and apoptosis during Drosophila eye development. Development 126, 5365–5372.
Hubbard, E.J., and Greenstein, D. (2005). Introduction to the germ line. WormBook 10–13. Hunt-Newbury, R., Viveiros, R., Johnsen, R., Mah, A., Anastas, D., Fang, L., Halfnight, E., Lee, D., Lin, J., Lorch, A., et al. (2007). High-throughput in vivo analysis of gene expression in Caenorhabditis elegans. PLoS Biol 5, e237.
Imae, R., Dejima, K., Kage-Nakadai, E., Arai, H., and Mitani, S. (2016). Endomembrane-
associated RSD-3 is important for RNAi induced by extracellular silencing RNA in both somatic and germ cells of Caenorhabditis elegans. Sci. Rep. 6, 28198.
Jeong, P.-Y., Jung, M., Yim, Y.-H., Kim, H., Park, M., Hong, E., Lee, W., Kim, Y.H., Kim, K., and Paik, Y.-K. (2005). Chemical structure and biological activity of the Caenorhabditis elegans dauer-inducing pheromone. Nature 433, 541–545.
Jia, K., Albert, P.S., and Riddle, D.L. (2002). DAF-9, a cytochrome P450 regulating C. elegans larval development and adult longevity. Development 129, 221–231.
Jia, K., Chen, D., and Riddle, D.L. (2004). The TOR pathway interacts with the insulin signaling pathway to regulate C. elegans larval development, metabolism and life span. Development 131, 3897–3906.
Jose, A.M., Smith, J.J., and Hunter, C.P. (2009). Export of RNA silencing from C. elegans tissues does not require the RNA channel SID-1. Proc. Natl. Acad. Sci. U. S. A. 106, 2283–2288. Kage-Nakadai, E., Imae, R., Suehiro, Y., Yoshina, S., Hori, S., and Mitani, S. (2014). A
conditional knockout toolkit for Caenorhabditis elegans based on the Cre/loxP recombination. PLoS One 9, e114680.
Karp, X. (2018). Working with dauer larvae. WormBook 2018, 1–19.
elegans. Genes Dev. 17, 3100–3111.
Karp, X., and Greenwald, I. (2004). Multiple roles for the E/Daughterless ortholog HLH-2 during C. elegans gonadogenesis. Dev. Biol. 272, 460–469.
Karp, X., and Greenwald, I. (2013). Control of cell-fate plasticity and maintenance of
multipotency by DAF-16/FoxO in quiescent Caenorhabditis elegans. Proc. Natl. Acad. Sci. U. S. A. 110, 2181–2186.
Killian, D.J., and Hubbard, E.J.A. (2005). Caenorhabditis elegans germline patterning requires coordinated development of the somatic gonadal sheath and the germ line. Dev. Biol. 279, 322– 335.
Kim, K., Sato, K., Shibuya, M., Zeiger, D.M., Butcher, R.A., Ragains, J.R., Clardy, J., Touhara,