Evidence for structural constraint on ovulin, a rapidly evolving Drosophila melanogaster seminal protein

Abstract

The egg-laying hormone ovulin (Acp26Aa) is among the most rapidly evolving proteins in the Drosophila genome. Against the background of ovulin's high sequence variability within and between species, we have identified highly conserved motifs that may play an important structural role. Using yeast two-hybrid and GST-pull-down assays, we show that ovulin interacts with itself. The C terminus of ovulin is necessary and sufficient for selfinteraction, with its C-terminal 45 aa playing a major role. Under nonreducing conditions, ovulin participates in a high-molecularmass complex, suggesting that it occurs in an oligomeric form. One or more of three predicted coiled-coil domains in the C terminus of ovulin may be involved in its self-interaction. These structural elements are conserved between species despite an overall rapid pace of evolution in ovulin's primary sequence. We therefore suggest that domains involved in ovulin's self-interaction form a conserved structural backbone for the protein, resulting in greater evolutionary flexibility at other sites.adaptive evolution ͉ conservation ͉ protein-protein interaction ͉ reproduction ͉ accessory gland proteins

Organization and regulation of sex-specific thioredoxin encoding genes in the genus Drosophila

“…The distances between the pairs of genes is given in base pairs. mating responses is the seminal protein Ovulin (or Acp26Aa; Tsaur and Wu 1997;Wong et al 2006). Ovulin is transferred to the female with the seminal fluid during copulation (Herndon and Wolfner 1995), and inside the female fly, it stimulates egg-laying after being processed, a step that requires components from both the male and female (Park and Wolfner 1995;Heifetz et al 2000).…”

Proteomics enhances evolutionary and functional analysis of reproductive proteins

“…While these sorts of screens -let alone the construction of a genome-wide RNAi library -are non-trivial, methods like a yeast two-hybrid screen (105) are feasible in non-model systems, since they require no prior knowledge of any particular gene or potential interactor.…”

Identity and transfer of male reproductive gland proteins of the dengue vector mosquito, Aedes aegypti: Potential tools for control of female feeding and reproduction

“…aegypti have been attributed to the effect of specific mRGPs in another Diptera species, Drosophila melanogaster (reviewed in Wolfner, 2002;Gillott, 2003;Chapman and Davies, 2004;Wolfner et al, 2005;Wong et al, 2006;. These proteins include: (1) simple peptides, including a "sex peptide" (Acp70A) that induces sexual refractoriness, increases the rate of egg production, and changes the feeding behavior and longevity of female Drosophila (Chapman et al, 2003;Liu and Kubli, 2003;Wigby and Chapman, 2005;Carvalho et al, 2006); (2) "prohormone-like" peptides, one of which (ovulin/Acp26Aa) stimulates ovulation (Heifetz et al, 2000); (3) large glycoproteins which are important for sperm storage (Neubaum and Wolfner, 1999) and other sperm-binding proteins; and (4) proteolysis regulators (Mueller et al, 2004;Ravi Ram et al, 2006;Mueller et al, 2007).…”