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PROTEOMIC AND UTR ANALYSES OF A RAPIDLY EVOLVING HYPERVARIABLE FAMILY OF VERTEBRATE PHEROMONES
Author(s) -
Wilburn Damien B.,
Bowen Kathleen E.,
Gregg Ronald G.,
Cai Jian,
Feldhoff Pamela W.,
Houck Lynne D.,
Feldhoff Richard C.
Publication year - 2012
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/j.1558-5646.2011.01572.x
Subject(s) - biology , vertebrate , sex pheromone , evolutionary biology , hypervariable region , genetics , zoology , gene
During the annual mating season, the mental gland of male plethodontid salamanders diverts its protein synthesizing capacity to the production of courtship pheromones that increase female receptivity. Plethodontid modulating factor (PMF), a highly disulfide‐bonded 7‐kDa pheromone, shows unusual hypervariability with each male expressing >30 isoforms. Twenty‐eight PMFs were purified and matched by proteomic analyses to cDNA sequences. In contrast to coding sequence hypervariability, the untranslated regions (UTRs) show extraordinary conservation, no predicted microRNA binding sites, and an overlapping triplet polyadenylation signal. Full‐length cDNA sequencing revealed three PMF gene classes containing subclasses of clustered sequences that support ≥13 PMF gene duplications. The unusual phenomena of hypervariable coding regions embedded within extremely conserved UTRs is proposed to occur by a disjunctive evolutionary process. During the short courtship season, the UTRs are hypothesized to subsume and coordinate the transcriptional and translational regulatory mechanisms of the mental gland. PMF, as a secreted protein with limited metabolic feedback in the male, is under minimal mutational restraint and thus has experienced highly accelerated rates of evolution. Consequently, plethodontid salamanders may provide a unique model for furthering our understanding of the selective forces that determine differential rates of gene duplication and evolution in protein families.