TEMPORAL PATTERNS IN THE APPEARANCE OF MATING TYPE INSTABILITY IN &lt;i&gt;PARAMECIUM CAUDATUM&lt;/i&gt;

Myohara, Koji; Hiwatashi, Koichi

doi:10.1266/jjg.50.133

Cited by 8 publications

(4 citation statements)

References 11 publications

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“…described here. In the previous paper (Myohara & Hiwatashi, 1975) we reported that selfing began to occur between 80 and 120 fissions after conjugation. Most of the clones used there were heterozygous at the mating-type locus.…”

Section: Discussionmentioning

confidence: 87%

Coordination on timing of gene expression inParamecium

Myohara

1980

Genet. Res.

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In Paramecium caudatum, syngen 3, cells become mature (i.e. capable of undergoing conjugation) by about 50 fissions after conjugation. Matingtype-instability, another mating characteristic, begins to occur between 80 and 120 fissions after conjugation in heterozygotes for the mating type locus (Myohara & Hiwatashi, 1975). Mating-type instability also occurs in dominant homozygotes, earlier than in heterozygotes. In two different early maturing mutants the homozygotes become mature 20 fissions earlier than in wild-type clones, and mating-type instabiliiy also begins earlier than in wild-type clones. The number of fissions from maturity to the occurrence of the mating type change does not differ.

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Section: Discussionmentioning

confidence: 87%

Coordination on timing of gene expression inParamecium

Myohara

1980

Genet. Res.

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“…Such a precursor hypothesis was first suggested for P. aurelia by Butzel (1955): the O mating‐type substances are the basic substances, and the activity of the Mt locus changes the O mating‐type substances into the E mating‐type substances. This hypothesis explained the fact that the unidirectional mating‐type change of selling stocks occurs naturally only in E mating types (Myohara and Hiwatashi 1975; Taub 1966). In selfing stock, some E cells change into O type by some cytoplasmic control or environmental factors, which switch Mt locus from an active to repressed state, and mating reaction occurs during the sexually reactive phase of one culture.…”

Section: Discussionmentioning

confidence: 99%

Odd Mating‐type Substances May Work as Precursor Molecules of Even Mating‐type Substances in Paramecium caudatum

Xu¹,

Kumakura²,

Kaku³

et al. 2001

J Eukaryotic Microbiology

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Mating-type substances are key molecules in the sexual recognition of the odd (O) and even (E) complementary mating-type cells in Paramecium caudatum. Indirect evidence suggested that the substances were proteins and were located on ventral surface cilia. Monoclonal antibodies inhibiting the mating reactivity of the O cells have been obtained. Using these antibodies, we tried to detect antigen molecules as dot-blot signals. Strong dot-blot signals of antigens were only detected from the mating reactive cells, but they were not detected from the well-fed and starved cells without mating reactivity. In addition to identifying the antigen on cilia and cytoplasm of the O cell, the antigen was detected from the cytoplasm of the E cells but never from their cilia. Furthermore, extracts of the E cells induced mating reaction with the living E cells but not with O cells. Thus, the O mating-type substances exist in the cytoplasm of the E mating-type cells, supporting strongly the hypothesis that O mating-type substances are precursor molecules of the E mating-type substances.

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“…The dual mating type E 3 E 12 was not a mixture of cells of different mating types, because whenever samples from several recipient clones were tested, a single cell expressed both type E 3 and E 12 simultaneously (data not shown). In P. caudatum, cells of type E change to type O when they age and are in late stationary phase (Myohara & Hiwatashi, 1975). Both the donor and the recipient were aged clones.…”

Section: (Ii) Intersyngenic Transplantations Of Type E Macronucleoplamentioning

confidence: 99%

Phenotypic conversion of mating type specificity induced by transplantation of macronucleoplasm inParamecium caudatum

Hori

Takahashi

1994

Genet. Res.

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According to the classical genetic analysis in Paramecium caudatum by Tsukii & Hiwatashi (1983), the E mating type of each syngen is expressed when the cell bears alleles specific for syngen at the Mt locus. The O mating type is expressed when cells are homozygous for the null allele, mt, at the Mt locus. In such mt/mt cells the O syngen specificity is determined by alleles at two other loci called MA and MB. In the study reported here, macronucleoplasmic transplantation technique was used to test the above hypothesis. When macronucleoplasm of type E 3 (mating type E of syngen 3) was injected into a macronucleus of type O 12 (mating type O of syngen 12), some recipients changed to type E of the donor syngen but some others changed to type E of the recipient syngen. Thus, syngen specificity of donor macronucleoplasm controlling type E was converted into that of the recipients, even though the latter has no gene that controls type E. When this transformant expressing type E of the recipient syngen was re-injected back into E of the other syngen, the expression of the converted mating type in some way continued in the recipient. This suggests that syngen specificity of gene Mt of the donor was changed to that of the recipients by intersyngenic transplantation of macronucleoplasm. We also obtained results suggesting that the gene dosage ratio of Mt to mt or Mt to MA and MB may be important for syngen specific expression of type E.

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TEMPORAL PATTERNS IN THE APPEARANCE OF MATING TYPE INSTABILITY IN <i>PARAMECIUM CAUDATUM</i>

Cited by 8 publications

References 11 publications

Coordination on timing of gene expression inParamecium

Coordination on timing of gene expression inParamecium

Odd Mating‐type Substances May Work as Precursor Molecules of Even Mating‐type Substances in Paramecium caudatum

Phenotypic conversion of mating type specificity induced by transplantation of macronucleoplasm inParamecium caudatum

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