Ciliary polypeptides and glycoconjugates of wild-type and mutant Tetrahymena thermophila: starved versus nonstarved.
To investigate the role of cilia in mating interactions of Tetrahymena thermophila, ciliary membrane-rich fractions were isolated from two wild-type strains, a non-discharge mucocyst mutant which possesses mating behavior similar to wild-type, and a mating mutant which is able to costimulate cells of complementary mating type but cannot enter into pair formation. In each case, proteins from the ciliary membrane-rich fractions of starved, mating-competent ("initiated") cells were compared with those from non-starved, mating-incompetent ("non-initiated") cells, by gel electrophoresis and lectin blotting. In stained gels, a 43 kDa polypeptide was reduced or absent in initiated cells but present in non-initiated cells, in all strains. In silver-stained gels, a 25 kDa polypeptide was present in all strains, both initiated and non-initiated. In blots probed with Con A-peroxidase, a 25 kDa glycoprotein was present in ciliary membrane fractions from non-initiated cells and absent in membranes of initiated cells of the two wild-type strains and the mucocyst mutant, but is present in initiated and non-initiated cells of the mating mutant (several hypotheses are presented to explain these findings). In addition, ciliary proteins of the mating mutant included at least two unique Con A-binding polypeptides. Our results support the idea that development of mating competence during starvation involves an extensive remodeling of ciliary membranes, and identify a 25 kDa glycoconjugate as having a potential role in control of pair formation during mating.
Cheng
L J
LJ
Department of Microbiology, University of Rhode Island, Kingston 02881.
Hufnagel
L A
LA
D000818:Animals; D002923:Cilia / Q000502:physiology* / Q000648:ultrastructure; D004591:Electrophoresis, Polyacrylamide Gel; D005508:Food Deprivation; D006001:Glycoconjugates / Q000235:genetics / Q000502:physiology*; D037102:Lectins; D008565:Membrane Proteins / Q000378:metabolism; D008854:Microscopy, Electron; D009154:Mutation; D010455:Peptides / Q000235:genetics / Q000502:physiology*; D015800:Protozoan Proteins / Q000235:genetics; D012098:Reproduction / Q000502:physiology; D016808:Tetrahymena thermophila / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure
D006001:Glycoconjugates; D037102:Lectins; D008565:Membrane Proteins; D010455:Peptides; D015800:Protozoan Proteins