Identification and characterization of a 38 kDa glycoprotein functionally associated with mating activity of Paramecium primaurelia.
In Paramecium primaurelia mating interactions take place immediately after mixing mating-competent cells of opposite mating types. The cells clump in clusters (mating reaction) and then separate in pairs. Previous results have shown that sialic acid-containing glycoconjugates are present on the cell surface and are involved in mating-cell pairing. In order to identify the sialic acid-containing glycoprotein(s), we first metabolically radiolabelled non-mating-competent cells with D-[6-(3)H]galactose, and then analyzed the radiolabelled proteins by anion exchange chromatography. We characterized a 38 kDa (gp38) sialic acid-containing glycoprotein and raised the corresponding polyclonal antibody by means of which we localized the antigen at the level of the oral region of non-mating-competent cells and on the ciliary surface of mating-competent cells. Immunoblot analysis of the ciliary protein fraction showed that the anti-gp38 serum interacted with a 38 kDa protein in both mating types I and II cells. We also demonstrated the functional activity of gp38 in the mating reaction by means of anti-gp38 antibody competition assays.
Ognibene
Marzia
M
Laboratorio di Biologia Molecolare, G. Gaslini Institute, Genoa, Italy.
Della Giovampaola
Cinzia
C
Trielli
Francesca
F
Focarelli
Riccardo
R
Rosati
Floriana
F
Umberta Delmonte Corrado
Maria
M
D000818:Animals; D000913:Antibodies, Protozoan / Q000378:metabolism / Q000494:pharmacology; D002462:Cell Membrane / Q000737:chemistry; D002923:Cilia / Q000737:chemistry; D006023:Glycoproteins / Q000302:isolation & purification / Q000378:metabolism*; D008018:Life Cycle Stages / Q000502:physiology; D010247:Paramecium / Q000737:chemistry / Q000502:physiology*; D037121:Plant Lectins / Q000378:metabolism; D015800:Protozoan Proteins / Q000302:isolation & purification / Q000378:metabolism*; D012098:Reproduction / Q000502:physiology; D054788:Ribosome Inactivating Proteins / Q000378:metabolism; D014316:Tritium / Q000378:metabolism
D000913:Antibodies, Protozoan; D006023:Glycoproteins; D037121:Plant Lectins; D015800:Protozoan Proteins; C050600:Sambucus nigra lectins; C039268:lectin, Canavalia; D014316:Tritium; D054788:Ribosome Inactivating Proteins