Induction of Heterothallic and Homothallic Zygotes in <i>Dictyostelium discoideum</i> by Ethylene

Amagai, Aiko

doi:10.1111/j.1440-169x.1992.tb00018.x

Cited by 10 publications

(9 citation statements)

References 21 publications

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“…The synthesis, role and regulation of ethylene in homothallic mating of D. mucoroides Dm7 has recently been reviewed (Amagai, 2009, 2011), hence we will only highlight aspects of this topic. In direct contrast to the inhibitory effects of cAMP, ethylene stimulates macrocyst formation in D. mucoroides (Amagai, 1984, 1992). This work provided a basis for the inhibition of sexual development by charcoal, CO 2 , mineral oil media and other ethylene antagonists observed by others (Amagai & Filosa, 1984; Filosa, 1979).…”

Section: Homothallic Sexual Developmentmentioning

confidence: 94%

Signalling and sex in the social amoebozoans

O’Day

Keszei

2011

Biological Reviews

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The social amoebozoans have a life tricycle consisting of asexual multicellular development leading to fruiting bodies, sexual multicellular development resulting in macrocysts, and unicellular development generating microcysts. This review covers the events of sexual development in the best-studied heterothallic (Dictyostelium discoideum) and homothallic (D. mucoroides) mating systems. Sexual development begins with pheromonal interactions that produce fusion-competent cells (gametes) which undergo cell and pronuclear fusion. Calcium- and calmodulin-mediated signalling mediates these early events. As they initiate chemotactic signalling, each zygote increases in size becoming a zygote giant cell. Using cyclic AMP (cAMP), the zygote chemotactically lures in amoebae and engulfs them in an act of cannibalistic phagocytosis. Chemotaxis proceeds more quickly than endocytosis because the breakdown products of cAMP (5-AMP, adenosine) bind to a presumptive adenosine receptor to inhibit sexual phagocytosis. This slowing of phagocytosis allows amoebae to accumulate around the zygote to form a precyst aggregate. Zygote giant cells also produce several other signalling molecules that feed back to regulate early events. The amoebae surrounding the zygote seal their fate as zygotic foodstuff by secreting a primary cellulose wall, the extracellular sheath, around the zygote and aggregated amoebae, which prevents their escape. Phagocytosis within this precyst continues until all peripheral amoebae are internalized as endocytes and the final macrocyst wall is formed. Endocyte digestion results in a mature macrocyst with a uniform cytoplasm containing a diploid nucleus. After detailing the morphological events of heterothallic and homothallic mating, we review the various intercellular signalling events and other mechanisms involved in each stage. This complete and comprehensive review sets the stage for future research on the unique events that characterize sex in the social amoebozoans.

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Section: Homothallic Sexual Developmentmentioning

confidence: 94%

Signalling and sex in the social amoebozoans

O’Day

Keszei

2011

Biological Reviews

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“…In heterothallic strains, zygote formation is also regulated by ethylene and cAMP. It was induced by ethylene, while it was inhibited by cAMP (Amagai, 1992;O'Day & Lydan, 1989). Incidentally, D. discoideum and its mating type, V12M2 cells also produce ethylene .…”

Section: Relation Between Ethylene Amounts and Zygote Formation Confimentioning

confidence: 97%

Regulatory Mechanism in Sexual and Asexual Cycles of Dictyostelium

Amagai¹

2012

Advances in Selected Plant Physiology Aspects

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“…26 In heterothallic strains, zygote formation is also regulated by ethylene and cAMP. It was induced by ethylene, while it was inhibited by cAMP 31,32. Accordingly, ethylene and cAMP may act on the regulation of zygote formation beyond the difference of mating types.…”

Section: The Function Of Ethylene In Zygote Formation At a Cellular Lmentioning

confidence: 97%

A Novel Function of Ethylene

Amagai

2009

Gene�Regul Syst Bio

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Abstract:The cellular slime mold, Dictyostelium mucoroides-7 (Dm7) exhibits clear dimorphism; macrocyst formation as a sexual process and sorocap formation as an asexual process. These two life cycles are regulated by two regulators, ethylene and cyclic AMP (cAMP). This is the fi rst report demonstrating a novel function of ethylene at the cellular level. That is, ethylene induces a zygote formed by cell fusion and subsequent nuclear fusion. Recently, the function of ethylene at the molecular level has been clarifi ed as it induces zygote formation through an enhanced expression of a novel gene, zyg1. The signaling pathway for induction or inhibition of zygote formation is now trying to be clarifi ed focusing on the ZYG1 protein.

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Induction of Heterothallic and Homothallic Zygotes in Dictyostelium discoideum by Ethylene

Cited by 10 publications

References 21 publications

Signalling and sex in the social amoebozoans

Signalling and sex in the social amoebozoans

Regulatory Mechanism in Sexual and Asexual Cycles of Dictyostelium

A Novel Function of Ethylene

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