Premium
Isolation and Structural Characterization of Two Water‐Borne Pheromones from Euplotes crassus , a Ciliate Commonly Known to Carry Membrane‐Bound Pheromones
Author(s) -
ALIMENTI CLAUDIO,
VALLESI ADRIANA,
FEDERICI SERGIO,
DI GIUSEPPE GRAZIANO,
FERNANDO DINI,
CARRATORE VITALE,
LUPORINI PIERANGELO
Publication year - 2011
Publication title -
journal of eukaryotic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 1066-5234
DOI - 10.1111/j.1550-7408.2011.00535.x
Subject(s) - biology , sex pheromone , pheromone , ciliate , amino acid , locus (genetics) , gene , genome , genetics , biochemistry , mating type
ABSTRACT. Ciliates comprise species synthesizing water‐diffusible mating type factors or pheromones and species synthesizing insoluble, cell membrane‐bound pheromones. Euplotes crassus has traditionally been placed in the latter group. In contrast with this notion, we found that E. crassus is a constitutive pheromone‐secreting ciliate, like other Euplotes species. From cell‐free filtrate preparations of the E. crassus strain L‐2D, we isolated two distinct pheromones, designated as E c ‐α and E c ‐1, and determined their complete amino acid sequences by combined chemical and genetic approaches. The E c ‐α pheromone sequence extends for 56 amino acid residues with six cysteines and shows a molecular mass of 6,183 Da, while the E c ‐1 pheromone sequence extends for 45 amino acid residues with 10 cysteines and shows a molecular mass of 4,840 Da. Marked structural differences distinguish the full‐length E c ‐α and E c ‐1 coding sequences, which have been cloned and characterized from the transcriptionally active macronuclear genome. They were taken as clear indication that the E c ‐α and E c ‐1 pheromones are specified by genes that are not allelic, but likely derived from a duplicated genetic locus of the transcriptionally silent micronuclear genome.