title: Odd mating-type substances may work as precursor molecules of even mating-type substances in Paramecium caudatum.
abstract: 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.
authors.affiliation: Institute of Biological Sciences, University of Tsukuba, Ibaraki, Japan.
authors.forename: X
authors.initials: X
authors.lastname: Xu
authors.forename: M
authors.initials: M
authors.lastname: Kumakura
authors.forename: E
authors.initials: E
authors.lastname: Kaku
authors.forename: M
authors.initials: M
authors.lastname: Takahashi
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000953:Antigens, Protozoan / Q000235:genetics / Q000378:metabolism; D002923:Cilia / Q000502:physiology; D003227:Conjugation, Genetic; D003593:Cytoplasm / Q000502:physiology; D010247:Paramecium / Q000235:genetics / Q000502:physiology*; D011498:Protein Precursors / Q000235:genetics / Q000378:metabolism*; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D012098:Reproduction / Q000235:genetics
chemical_list: D000911:Antibodies, Monoclonal; D000953:Antigens, Protozoan; D011498:Protein Precursors; D015800:Protozoan Proteins