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Yamada Y, Minamisawa H, Fukuzawa M, Kawata T, Oohata AA. Prespore cell inducing factor, psi factor, controls both prestalk and prespore gene expression in Dictyostelium development. Dev Growth Differ 2010; 52:377-83. [PMID: 20500764 DOI: 10.1111/j.1440-169x.2010.01177.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Prespore cell-inducing (psi, psi) factor (PsiA), encoded by the psiA gene of Dictyostelium, is a secreted signal glycoprotein that induces prespore cell differentiation when added to monolayer cultures. In situ hybridization during normal development showed that the psiA gene is highly expressed in scattered cells at the mound stage and in prespore cells at the onset of culmination. The conventional prespore-cell marker genes, cotC and pspA, were expressed normally in psiA(-) and psiA overexpressing strains. Expressions of rnrB and cudA are repressed in the prestalk cells of a wild type slug to render prespore specific pattern. However, a promoter-reporter fusion gene, rnrB:lacZ, showed an ectopic expression in the prestalk cells of the psiA(-) strain while cudA(psp):lacZ did so in those of the psiA overexpressing strain. Overexpression of psiA delayed expression of the prestalk specific gene, ecmB, during development, while knocking out psiA promoted its expression. In addition, overexpression inhibited DIF-1-induced stalk formation in monolayer cultures. Together with the known prespore inducing activity, the results indicate that PsiA regulates both prespore and prestalk/stalk cell differentiation. These results indicate that PsiA is also involved in prestalk cell differentiation.
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Affiliation(s)
- Yoko Yamada
- Biological Laboratory, Kansai Medical University, Hirakata, Osaka, Japan
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Kawata T, Nakagawa M, Shimada N, Fujii S, Oohata AA. A gene encoding, prespore-cell-inducing factor in Dictyostelium discoideum. Dev Growth Differ 2004; 46:383-92. [PMID: 15367206 DOI: 10.1111/j.1440-169x.2004.00749.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Two factors that exist in conditioned medium (CM) of Dictyostelium discoideum induce amoebae to differentiate into prespore cells when they are incubated at a very low cell density in submerged monolayer culture. Previously, we purified one of them, a glycoprotein factor with an apparent molecular mass of 106 kDa, and we named it psi factor (psi, prespore-inducing factor). Based on the partial amino acid sequence of the purified psi factor, we have isolated the corresponding cDNA clone, which is expressed maximally at the loose mound stage. The cDNA encodes a novel protein and the predicted molecular mass of the mature secreted protein is 60 kDa. Knockout mutant strains of the psi factor gene, psiA(-), were created by targeted integration. Although these mutant strains appear to develop normally, CM from these mutants showed reduced prespore-cell-inducing activity. Rescuing the mutant strains by expression of psi factor under control of a constitutive promoter causes overproduction of psi factor protein and CM from such cells showed a 20-fold higher level of prespore-cell-inducing activity than that from wild-type cells. Further, CM from parental cells induced prespore cell division, while that from psiA null strains showed no cell division inducing activity. Our results indicate that psi factor protein is a novel type of growth factor that does not belong to any of the families of growth factor so far identified in animals.
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Affiliation(s)
- Takefumi Kawata
- Department of Biology, Faculty of Science, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274-8510, Japan
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Anjard C, van Bemmelen M, Véron M, Reymond CD. A new spore differentiation factor (SDF) secreted by Dictyostelium cells is phosphorylated by the cAMP dependent protein kinase. Differentiation 1997; 62:43-9. [PMID: 9373946 DOI: 10.1046/j.1432-0436.1997.6210043.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Upon starvation, Dictyostelium discoideum unicellular amoebae form a multicellular organism leading to the development of a fruiting body containing spores. Single cells of sporogenous mutants, unlike wild type cells, are able to differentiate into spores under specific conditions. We show in this report that overexpression of the catalytic subunit of the cAMP dependent protein kinase (PKA), not only renders the cells sporogenous, but is also accompanied by the production/release of a diffusible spore differentiation factor (SDF). SDF is a small, thermostable phospho-polypeptide. In vitro dephosphorylation reduces SDF spore differentiation capacity, which can be regained in vitro by PKA phosphorylation. These results indicate that SDF is a PKA substrate and might be activated in vivo by this protein kinase. Since spore differentiation requires PKA catalytic subunit activation, we conclude that the response of prespore cells to SDF involves an intracellular pathway dependent on PKA.
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Affiliation(s)
- C Anjard
- Unité de régulation enzymatique des activités celluaires, CNRS-UMR 321, Institut Pasteur, Paris, France
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Oohata AA. Factors controlling prespore cell differentiation in Dictyostelium discoideum: minute amounts of differentiation-inducing factor promote prespore cell differentiation. Differentiation 1995; 59:283-8. [PMID: 8882813 DOI: 10.1046/j.1432-0436.1996.5950283.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Amoebae of strain V12M2 differentiate efficiently into prespore cells without cell contact in a salt solution containing cAMP, if the pH of the medium is maintained suitably acidic using a restricted buffer [31]. Under such conditions, most cells differentiate into prespore cells at pH 5.2. Using this developmental system, the elements controlling prespore-cell differentiation were analyzed. First, the dependence on cell density was examined. At a very low density (10(2) cells/cm2), most cells did not differentiate. As the density was increased the proportion of prespore cells differentiating increased, reaching a maximum at 5 x 10(3) cells/cm2. Conditioned medium could mimic the effects of cell density on cell differentiation. These findings suggest the presence of factor(s) released into the medium which are involved in inducing prespore-cell differentiation. The conditioned medium was found to contain at least two prespore-inducing components; one is a novel factor(s) and the other is DIF, which has previous only been considered to repress prespore-cell differentiation. These findings were supported by experiments using a DIF-deficient mutant, HM44.
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Affiliation(s)
- A A Oohata
- Biological Laboratory, Kansai Medical University, Osaka, Japan
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Yoshida H, Yamada Y, Okamoto K. DC6, a novel type of Dictyostelium discoideum gene regulated by secreted factors but not by cAMP. Differentiation 1991; 46:161-6. [PMID: 1717330 DOI: 10.1111/j.1432-0436.1991.tb00877.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We have isolated a gene, DC6, which is induced in the early aggregative stages of development in Dictyostelium discoideum. The increase in DC6 expression is dependent on high cell density, indicating that cellular interactions are required for DC6 induction. In low-cell-density cultures, the induction of DC6 occurs if supplied with conditioned medium of developing cells, suggesting that secreted factors are involved in DC6 induction. The expression of DC6 is not affected (1) in the presence of caffeine or adenosine, which block the production or the action of cAMP pulses, (2) in the presence of high concentrations of cAMP, or (3) in mutant strains (Synag7 and FrigidA), which are defective in transduction pathways of cAMP pulse signals. These results indicate that the induction of DC6 does not require extracellular cAMP pulse signals, which are known to regulate the expression of many genes in the early development. Independence of cAMP signals and dependence on other unknown cellular interactions are prominent characteristics of DC6.
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Affiliation(s)
- H Yoshida
- Department of Botany, Faculty of Science, Kyoto University, Japan
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Richards AJ, Corney AJ, Hames BD. Cell-type-specific genes expressed late in Dictyostelium development show markedly different responses to 3'5' cyclic AMP. Mol Microbiol 1990; 4:1279-91. [PMID: 2177818 DOI: 10.1111/j.1365-2958.1990.tb00707.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The maintenance of late gene expression by 3'5' cyclic AMP was re-examined using several newly isolated cell-type-specific genes. Expression of all the prespore-enriched genes ceased immediately upon disaggregation of developing cells and pre-existing mRNA was rapidly degraded. For most genes, cAMP had little or no effect either alone or in combination with conditioned medium factors. The expression of the non-cell-type-specific genes 7E and 2C also ceased upon cell disaggregation but cAMP triggered a full re-induction of expression although the timing of the response differed markedly between these two genes. In contrast to earlier interpretations, these data argue that for none of these late prespore genes is cAMP alone sufficient for the maintenance of expression. The responses of the two prestalk mRNAs examined were gene-specific. Prestalk 5D mRNA decayed slowly upon disaggregation and was partially stabilized by cAMP whereas prestalk 5G mRNA increased upon disaggregation and was inhibited by cAMP.
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Affiliation(s)
- A J Richards
- Department of Biochemistry, University of Leeds, UK
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Yamada Y, Okamoto K. Three steps in prespore differentiationin Dictyostelium discoideum with different requirements of cellular interaction. Differentiation 1990. [DOI: 10.1111/j.1432-0436.1990.tb00540.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Kwong L, Weeks G. The effects of presumptive morphogens on prestalk and prespore gene expression in monolayers of Dictyostelium discoideum. Differentiation 1990. [DOI: 10.1111/j.1432-0436.1990.tb00541.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Corney AJ, Richards AJ, Phillpots T, Hames BD. Developmental regulation of cell-type-enriched mRNAs in Dictyostelium discoideum. Mol Microbiol 1990; 4:613-23. [PMID: 2161991 DOI: 10.1111/j.1365-2958.1990.tb00630.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
We describe sixteen new families of cDNA clones representing mRNAs that are expressed preferentially in either prespore or prestalk cells during development of Dictyostelium discoideum and two new mRNAs that are expressed in a non-cell-type-specific manner. None of the prespore-enriched mRNAs are detectable in Dictyostelium cells until 13-15 h of development but then they increase dramatically and peak at 18-22 h. Upon dissociation of developing aggregates, all these mRNAs rapidly decay to low levels. In marked contrast to data presented for prespore genes by other workers, cyclic AMP either has no effect on the mRNA levels in dissociated cells or is only weakly effective in restoring normal expression. A prestalk-enriched mRNA examined, 5G mRNA, is similarly expressed late in development but is also expressed in vegetative cells. The level of 5G mRNA is only moderately affected by cell disaggregation.
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Affiliation(s)
- A J Corney
- Department of Biochemistry, University of Leeds, UK
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Kwong L, Weeks G. Studies on the accumulation of the differentiation-inducing factor (DIF) in high-cell-density monolayers of Dictyostelium discoideum. Dev Biol 1989; 132:554-8. [PMID: 2466719 DOI: 10.1016/0012-1606(89)90250-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A number of factors that have been shown to influence cell type determination in Dictyostelium discoideum were assessed for their effects on the accumulation of the stalk cell differentiation-inducing factor (DIF) in high-cell-density monolayers of strain V12-M2. DIF accumulation is markedly enhanced by low pH, butyrate, and the proton pump inhibitor diethylstilbestrol (DES), conditions that induce stalk cell formation in low-cell-density monolayers in the absence of added DIF. These results are discussed in relation to a model for cell type determination recently proposed by (J.D. Gross, M.J. Peacey, and R. Pogge Von Strandmann (1988, Differentiation, 38: 91-98). DIF accumulates in high-cell-density monolayers after the cells have become independent of cyclic AMP for stalk cell formation. This accumulation is greatly enhanced by the addition of cyclic AMP. This result may explain why cyclic AMP stimulates stalk cell formation in low-density monolayers in the presence of suboptimal levels of DIF, following preincubation in the presence of saturating levels of cyclic AMP (L. Kwong, A. Sobolewski, and G. Weeks, 1988, Differentiation 37, 1-6). Adenosine has no effect on DIF accumulation in high-cell-density monolayers.
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Affiliation(s)
- L Kwong
- Department of Microbiology, University of British Columbia, Vancouver, Canada
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Kwong L, Sobolewski A, Weeks G. The effect of cAMP on differentiation inducing factor (DIF)-mediated formation of stalk cells in low-cell-density monolayers of Dictyostelium discoideum. Differentiation 1988. [DOI: 10.1111/j.1432-0436.1988.tb00789.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Blaschke A, Weijer C, MacWilliams H. Dictyostelium discoideum: Cell-type proportioning, cell-differentiation preference, cell fate, and the behavior of anterior-like cells in Hs1/Hs2 and G+/G− mixtures. Differentiation 1986. [DOI: 10.1111/j.1432-0436.1986.tb00549.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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