The high-multiple mating system of Euplotes crassus is known to be controlled by multiple alleles segregating at a single locus and manifesting relationships of hierarchical dominance, so that heterozygous cells would produce a single mating-type substance (pheromone). In strain L-2D, now known to be homozygous at the mating-type locus, we previously identified two pheromones (Ec-a and Ec-1) characterized by significant variations in their amino acid sequences and structure of their macronuclear coding genes. In this study, pheromones and macronuclear coding genes have been analyzed in strain POR-73 characterized by a heterozygous genotype and strong mating compatibility with L-2D strain. It was found that POR-73 cells contain three distinct pheromone coding genes and, accordingly, secrete three distinct pheromones. One pheromone revealed structural identity in amino acid sequence and macronuclear coding gene to the Ec-a pheromone of L-2D cells. The other two pheromones were shown to be new and were designated Ec-2 and Ec-3 to denote their structural homology with the Ec-1 pheromone of L-2D cells. We interpreted these results as evidence of a phenomenon of gene duplication at the E. crassus mating-type locus, and lack of hierarchical dominance in the expression of the macronuclear pheromone genes in cells with heterozygous genotypes.
|Autori:||Adriana, Vallesi; Claudio, Alimenti; Sergio, Federici; DI GIUSEPPE, Graziano; Dini, Fernando; Graziano, Guella; Pierangelo, Luporini|
|Titolo:||Evidence for Gene Duplication and Allelic Codominance (not Hierarchical Dominance) at the Mating-Type Locus of the Ciliate, Euplotes crassus|
|Anno del prodotto:||2014|
|Digital Object Identifier (DOI):||10.1111/jeu.12140|
|Appare nelle tipologie:||1.1 Articolo in rivista|