cAMP production by adenylyl cyclase G induces prespore differentiation in<i>Dictyostelium</i>slugs

Álvarez-Curto, Elisa; Saran, Shweta; Meima, Marcel E; Zobel, Jenny; Scott, Claire; Schaap, Pauline

doi:10.1242/dev.02775

Cited by 42 publications

(58 citation statements)

References 38 publications

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“…Cells from dissociated slugs were incubated with the cAMP phosphodiesterase (PDE) inhibitors DTT and 3-isobutyl-1-methylxanthine (IBMX) (15) in the presence and absence of 2 μM c-di-GMP. In slugs, cAMP is produced by three adenylate cyclases, ACA, ACG, and ACR (3,16,17). Addition of PDE inhibitors allows cAMP to accumulate to about 20 pmol per 10 7 cells, whereas stimulation with c-di-GMP causes a further twofold increase (Fig.…”

Section: C-di-gmp Regulation and Expression Patterns Of Putative C-dimentioning

confidence: 99%

“…This program is initiated by starvation, which causes cells to collect into aggregates, using secreted cAMP pulses, produced by adenylate cyclase A (ACA), as a chemoattractant (2). Secreted cAMP produced by the adenylate cyclases ACG and ACR additionally induces differentiation of prespore cells (3). The prespore cells in turn synthesize the polyketide Differentiation-Inducing Factor 1 (DIF-1), which causes differentiation into precursors of some somatic cell types (4).…”

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Adenylate cyclase A acting on PKA mediates induction of stalk formation by cyclic diguanylate at the Dictyostelium organizer

Chen

Singh

Callebaut

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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Coordination of cell movement with cell differentiation is a major feat of embryonic development. The Dictyostelium stalk always forms at the organizing tip, by a mechanism that is not understood. We previously reported that cyclic diguanylate (c-di-GMP), synthesized by diguanylate cyclase A (DgcA), induces stalk formation. Here we used transcriptional profiling of dgca− structures to identify target genes for c-di-GMP, and used these genes to investigate the c-di-GMP signal transduction pathway. We found that knockdown of cAMP-dependent protein kinase (PKA) activity in prestalk cells reduced stalk gene induction by c-di-GMP, whereas PKA activation bypassed the c-di-GMP requirement for stalk gene expression. c-di-GMP caused a persistent increase in cAMP, which still occurred in mutants lacking the adenylate cyclases ACG or ACR, or the cAMP phosphodiesterase RegA. However, both inhibition of adenylate cyclase A (ACA) with SQ22536 and incubation of a temperature-sensitive ACA mutant at the restrictive temperature prevented c-di-GMP–induced cAMP synthesis as well as c-di-GMP–induced stalk gene transcription. ACA produces the cAMP pulses that coordinate Dictyostelium morphogenetic cell movement and is highly expressed at the organizing tip. The stalk-less dgca− mutant regained its stalk by expression of a light-activated adenylate cyclase from the ACA promoter and exposure to light, indicating that cAMP is also the intermediate for c-di-GMP in vivo. Our data show that the more widely expressed DgcA activates tip-expressed ACA, which then acts on PKA to induce stalk genes. These results explain why stalk formation in Dictyostelia always initiates at the site of the morphogenetic organizer.

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Section: C-di-gmp Regulation and Expression Patterns Of Putative C-dimentioning

confidence: 99%

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confidence: 99%

Adenylate cyclase A acting on PKA mediates induction of stalk formation by cyclic diguanylate at the Dictyostelium organizer

Chen

Singh

Callebaut

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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“…Western hybridization was essentially carried out as given in Swer et al, (2014b) while immunocytochemistry was performed according to Alvarez-Curto et al, (2007). Anti-ODC1 (#HPA001536) and anti-actin (#04-1040) antibodies were purchased from Sigma.…”

Section: Protein Detection By Western Hybridization and Immunocytochementioning

confidence: 99%

Cloning, expression and characterization of the ornithine decarboxylase gene from Dictyostelium discoideum

Kumar¹,

Rafia²,

Saran³

2014

Int. J. Dev. Biol.

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Ornithine decarboxylase (ODC) is a rate limiting enzyme in polyamine synthesis that decarboxylates ornithine to form the diamine putrescine. We report here the isolation, expression and characterization of a homolog of ODC from Dictyostelium discoideum. DdODC is conserved and shows sequence and structural homology with that from human. Both ODC transcript and protein are expressed at all stages of development and show high expression in prestalk/stalk cells. It is cytosolic and predominantly perinuclear in localization. Both overexpression of DdODC and putrescine treatment resulted in inhibition of cell proliferation. KEY WORDS: D. discoideum, ODC expression, putrescinePolyamines are ubiquitously present from bacteria to mammals Tabor 1985, Janne 2004) and regulate cell growth, proliferation, differentiation and cell death. The fast proliferating prokaryotes mostly contain putrescine and spermidine (Tabor and Tabor 1976) while the slow proliferating eukaryotes predominantly have spermidine and spermine (Fillingame 1975). A decrease in intracellular polyamines occurs during aging (Minois et al., 2011) but it still remains unclear whether this is a cause or consequence of aging. Addition of exogenous spermidine can extend lifespan in various animal models through epigenetic modifications, induction of autophagy and suppression of necrosis (Eisenberg et al., 2009).Ornithine decarboxylase (ODC, EC 4.1.1.17) catalyses the first and the rate limiting step of polyamine biosynthesis where Lornithine is converted to putrescine (Heller et al., 1976). It is strictly regulated during development (Heby and Persson 1990) and is involved in synthesis of spermidine and spermine. Decarboxylation of ornithine by ODC is the only pathway for de novo synthesis of polyamines in mammals and higher eukaryotes. The ability to strictly regulate cellular polyamine levels within a very narrow range is critical since extreme levels of polyamines (high or low) result in damaging effects, both on life of the cell and organism as a whole (Pegg and McCann 1982).This study was undertaken to understand the role of putrescine, which is the most abundant polyamine found in Dictyostelium discoideum (Saran 1998 Abbreviations used in this paper: DdODC, Dictyostelium discoideum ODC; ODC, ornithine decarboxylase.grow and divide mitotically but upon starvation and in response to the chemoattractant, cAMP, they enter the developmental phase to ultimately form a fruiting body consisting of dead vacuolated stalk cells and viable spores. Since ODC is responsible for the formation of putrescine we characterized this enzyme. Harris and North (1982) did not find any significant ODC activity during development but Campagne and Lowik (1985) have reported high activity at the slug stage. Our earlier report (Saran 1998) has shown high putrescine levels during slug stage. This is the first report on molecular cloning, expression and characterization of a putative ODC-like sequence from D. discoideum. We found it to be structurally conserved and predomina...

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“…In the 1990s, it became clear that, in addition to extracellular cAMP, intracellular cAMP acting on PKA was also required for prespore differentiation and was, furthermore, essential for spore and stalk maturation and for the control of spore germination (Harwood et al, 1992;Hopper et al, 1993;Van Es et al, 1996). For stalk and spore maturation, cAMP is produced by adenylate cyclase R (ACR), whereas cAMP for induction of prespore differentiation and control of spore germination is produced by adenylate cyclase G (ACG) Van Es et al, 1996;Alvarez-Curto et al, 2007). ACR harbours seven transmembrane domains and is embedded in the nuclear membrane of prestalk cells Alvarez-Curto et al, 2007;Chen et al, 2011).…”

Section: Camp Regulation Of Fruiting Body Formationmentioning

confidence: 99%

Evolutionary crossroads in developmental biology: Dictyostelium discoideum

Schaap

2011

Development

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SummaryDictyostelium discoideum belongs to a group of multicellular life forms that can also exist for long periods as single cells. This ability to shift between uni-and multicellularity makes the group ideal for studying the genetic changes that occurred at the crossroads between uni-and multicellular life. In this Primer, I discuss the mechanisms that control multicellular development in Dictyostelium discoideum and reconstruct how some of these mechanisms evolved from a stress response in the unicellular ancestor.Key words: Evolution of multicellularity, Social amoeba, Encystation, Sporulation, Dictyostelium IntroductionThe social amoebas, or Dictyostelia, are a group of organisms that become multicellular by aggregation and then proceed to build fruiting bodies that consist of stalk cells and spores (see Glossary, Box 1). This developmental cycle is a response to starvation, and involves both highly coordinated cell movement and a tightly controlled programme of cell differentiation. Social amoebas belong to the supergroup of Amoebozoa (see Glossary, Box 1), a sister group to the clade of Opisthokonts (see Glossary, Box 1), which contains the animals and fungi. All supergroups contain unicellular protist-like organisms (see Glossary, Box 1) and, in several groups, multicellular life forms have evolved independently (Minge et al., 2009).The Amoebozoa supergroup consists mainly of unicellular amoeba-like organisms that have a simple life cycle. The feeding amoeba or trophozoite turns into a dormant cyst when faced with food shortage, drought or other life-threatening circumstances (Cavalier-Smith et al., 2004). Several clades of Amoebozoa have given rise to protostelid-like organisms (see Glossary, Box 1), which form a very simple fruiting body (see Glossary, Box 1) that consists of a single spore that sits on a simple stalk made by the same cell (Shadwick et al., 2009). However, only the Dictyostelia are able to form multicellular fruiting bodies that contain up to a million cells (Fig. 1).There are ~120 known species of Dictyostelia and a molecular phylogeny has been constructed to reveal the order in which they evolved (Schaap et al., 2006). The phylogeny subdivides species into four major groups (Fig. 2), with the model social amoeba Dictyostelium discoideum belonging to the most recently diverged group 4. Many species in groups 1-3 can still encyst as single cells when conditions are unfavourable for aggregation. However, group 4 species have lost the ability to encyst. Strikingly, all group 4 species tested secrete cyclic adenosine monophosphate (cAMP) to act as a chemoattractant for aggregation. This is most unusual, because almost all other organisms only use cAMP inside the cell to transduce the effect of other secreted stimuli, such as hormones, mating factors and neurotransmitters. None of the species in groups 1-3 uses cAMP for aggregation; some use glorin, a modified dipeptide of glutamate and ornithine, whereas others use folic acid, pterin or other as yet unidentified chemoattractants (Schaap e...

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cAMP production by adenylyl cyclase G induces prespore differentiation inDictyosteliumslugs

Cited by 42 publications

References 38 publications

Adenylate cyclase A acting on PKA mediates induction of stalk formation by cyclic diguanylate at the Dictyostelium organizer

Adenylate cyclase A acting on PKA mediates induction of stalk formation by cyclic diguanylate at the Dictyostelium organizer

Cloning, expression and characterization of the ornithine decarboxylase gene from Dictyostelium discoideum

Evolutionary crossroads in developmental biology: Dictyostelium discoideum

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