Self and non-self recognition between gametes of the ascidian,Halocynthia roretzi

Fuke, Masako T.

doi:10.1007/bf00848815

Cited by 60 publications

(41 citation statements)

References 12 publications

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“…Morris (1962) recorded low levels of self-fertilization and high levels of cross-fertilization in numerous in vitro trials with gametes of the pyurid Herdmania momus; the chorion was regarded as the site of the block to self-fertilization. A high level of self-sterility has also been reported in a second pyurid, Halocynthia roretzj, by Fuke (1983), again with the chorion suggested as the site of discrimination between autologous and heterologous sperm.…”

Section: Introductionmentioning

confidence: 84%

Prevalence of cross-fertilization in the hermaphroditic compound ascidian Diplosoma listerianum

Ryland¹,

Bishop²

1990

Mar. Ecol. Prog. Ser.

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ABSTRACT. Experiments with several clones of Diplosoma ljsten'anum (Mllne Edwards) maintained in culture indicated that the majority produced sexual progeny (larvae) predominantly or exclusively by cross-rather than self-fertilization. The extent of true selfing, if any, was not established. Arrested oocyte development was observed in several clones kept in reproductive isolation. Full oocyte development could b e triggered in these by placing other genetic individuals in the same container, even though the different clones were not in phys~cal contact

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Section: Introductionmentioning

confidence: 84%

Prevalence of cross-fertilization in the hermaphroditic compound ascidian Diplosoma listerianum

Ryland¹,

Bishop²

1990

Mar. Ecol. Prog. Ser.

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“…Fuke removed follicle cells from eggs by treatment with calcium-free seawater, then reattached them to defolliculated eggs from a different individual in calcium-enriched seawater. Such a «mosaic» egg recovered the ability to be fertilized, and it was revealed that the VC but not follicle cells are responsible for the SI specificity (Fuke, 1983). Since a difference between the binding capabilities of sperm to the nonself-and self-VC is not obvious in H. roretzi as it is in C. intestinalis, sperm are Binding between HrUrain and HrVC70 is weakened then sperm is detached from the VC.…”

Section: Hrvc70 a Candidate Allorecognition Protein During Fertilizamentioning

confidence: 99%

“…It is known that mature oocytes, but not immature oocytes, are self-sterile and that short treatment (1 min) of mature oocytes with acidic seawater (pH 2 to 3) allows self-fertilization (Fuke, 1983;Sawada, 2002). Furthermore, it is reported that the acquisition of self-sterility during oocyte maturation is blocked by trypsin inhibitors and that exogenously added trypsin stimulates the acquisition of selfsterility (Fuke and Numakunai, 1996;.…”

mentioning

confidence: 99%

Allorecognition mechanisms during ascidian fertilization

Harada¹,

Sawada²

2008

Int. J. Dev. Biol.

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Ascidians (primitive chordates) are hermaphroditic animals, releasing sperm and eggs nearly simultaneously. But, many ascidians, including Ciona intestinalis and Halocynthia roretzi, show self-sterility or preference for cross-fertilization rather than self-fertilization. The molecular mechanisms underlying this allorecognition process are only poorly understood. We recently identified the genes responsible for self-incompatibility in C. intestinalis by a positional cloning: sperm-borne polycystin 1-like receptor, referred to as s-Themis, and its fibrinogen-like ligand called v-Themis on the vitelline coat (VC) are highly polymorphic and appear to be responsible for allorecognition in the fertilization of C. intestinalis. In H. roretzi, on the other hand, we revealed that HrVC70, a 70-kDa main component of the VC consisting of 12 epidermal-growthfactor (EGF)-like repeats, is a candidate allorecognition protein, since the attachment of this protein to the VC during oocyte maturation and its detachment by weak acid are closely linked to the gain and the loss of self-sterility, respectively, and also since nonself-sperm rather than selfsperm efficiently bound to HrVC70-agarose. As a binding partner of HrVC70, a 35-kDa GPIanchored glycoprotein in sperm lipid rafts, referred to as HrUrabin, was identified: HrUrabin appears to play a key role in allorecognizable sperm binding to HrVC70 during fertilization. In the present review, we describe the current progress on the molecular bases of allorecognition, or self-incompatibility, during ascidian fertilization, by considering the SI systems in another organisms including fungies and flowering plants.

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“…However, several studies presented good evidence that not only the VC but also the FCs are involved in the self-nonself recognition process (Fuke, 1983; DeSantis, 1991;Pinto et al, 1995). In Ciona a self sterility promoting factor released from the FCs was suggested to be deposited on the VC (Marino et al, 1998).…”

Section: B a B A The Ascidian Egg Coat In Fertilization 529mentioning

confidence: 99%

The ascidian egg envelope in fertilization: structural and molecular features

Honegger¹,

Koyanagi²

2008

Int. J. Dev. Biol.

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In this report, unpublished and recent findings concerning the structure and function of the ascidian egg coat are compiled in context with fertilization. In the initial stage of ascidian fertilization, sperm interact with a complex egg investment that consists of a layer of follicle cells attached to an acellular vitelline coat. Increasing evidence exists that ascidian sperm are activated at their encounter with the follicle cells. The molecular basis of sperm-follicle cell interactions is discussed in context with sperm binding, membrane proteins and sperm bound glycosidase. The model that suggests a block to polyspermy established by glycosidase released from the follicle cells on fertilization is evaluated and compared with assured facts. Although a number of questions remain to be answered, our recent findings that a cloned β-hexosaminidase from P. mammillata binds exclusively to the follicle cells of unfertilized but not fertilized eggs, indicates that the follicle cells participate in the block to polyspermy. A dual function, mediating sperm activation and a block to polyspermy attributes to the ascidian follicle cells a key position in fertilization. KEY WORDS: fertilization, ascidian, egg coat, follicle cellThe ascidian egg envelope: a survey of the structural features Ascidian eggs are surrounded by an acellular envelope called chorion or vitelline coat (VC) to which follicle cells (FCs) adhere externally and test cells (TC) internally. Multitudinous functions have been attributed to the egg envelope as entity and to each of its structural components. In the present paper we focus on the role of the egg envelope in fertilization particularly the function of FCs in sperm egg-interaction.The pictures of Phallusia mammillata eggs ( Fig. 1 A,B) give a view of the egg and egg envelope representative for solitary and colonial ascidians with external fertilization. The egg of about 130 µm in diameter exhibits a relatively smooth plasma membrane with only few short microvilli. It is surrounded by an acellular VC with test cells attached to the inner and follicle cells to the outer surface. In most solitary species, the follicle cells are cubical or columnar or rarely tall cone-shaped as in Ciona. Test cells typically adhere to the inner matrix of the VC not to the egg surface. In some species, they form an almost closed sheet in others they are loosely arranged in groups. Although scanning electron microscopy (SEM) pictures reveal a good 3D impression, Int. J. Dev. Biol. 52: 527-533 (2008) the real dimension of the highly hydrated VC layers is never preserved and the highly vacuolated follicle cells are shriveled. This is also the case if conventional preparation is applied for transmission electron microscopy (TEM). Due to dehydration the VC appears as a relatively thin bi-or tripartite filamentous structure of about 400 to 900 nm (Honegger, 1986;Xie and Honegger, 1993;Cloney, 1995;Burighel and Cloney, 1997). Especially the filamentous structure of the inner VC layer mostly appears compressed and...

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Self and non-self recognition between gametes of the ascidian,Halocynthia roretzi

Cited by 60 publications

References 12 publications

Prevalence of cross-fertilization in the hermaphroditic compound ascidian Diplosoma listerianum

Prevalence of cross-fertilization in the hermaphroditic compound ascidian Diplosoma listerianum

Allorecognition mechanisms during ascidian fertilization

The ascidian egg envelope in fertilization: structural and molecular features

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