Academic journal article Genetics

MicroRNAs Influence Reproductive Responses by Females to Male Sex Peptide in Drosophila Melanogaster

Academic journal article Genetics

MicroRNAs Influence Reproductive Responses by Females to Male Sex Peptide in Drosophila Melanogaster

Article excerpt

REPRODUCTION is a fundamental biological process and it is well established that mating itself initiates a mul- titude of physiological and behavioral postmating changes in females. Insights into the gene expression changes un- derlying mating have been gained from studies in the fruit fly Drosophila melanogaster (Lawniczak and Begun 2004; McGraw et al. 2004; Mack et al. 2006; Innocenti and Morrow 2009). D. melanogaster males transfer not only sperm in their ejaculates, but also up to ~I30 different seminal fluid peptides (Sfps) (Findlay et al. 2008; Ayroles et al. 2011). Many of the striking postmating responses of females to mating are mediated by the effects of these Sfps (Chapman 2001; Gillot 2003; Ram and Wolfner 2007a; Wolfner 2009). It is therefore of significant, fundamental interest to understand the detailed mechanisms underlying the profound reprogramming in gene expression that occurs in females due to Sfp receipt. Through this understanding, it will be possible to determine (i) how the extensive changes required to effectively coordinate reproduction are regulated and (ii) to what extent these processes are shaped by sexual selection and sexual conflict.

Our knowledge of the phenotypes and functions of in- dividual Sfps in D. melanogaster is rapidly increasing (Herndon and Wolfner 1995; Neubaum and Wolfner 1999; Tram and Wolfner 1999; Mueller et al. 2007; Ram and Wolfner 2007a; LaFlamme et al. 2012). One well-characterized Sfp, on which we focus in this study, is the so-called "sex peptide" (SP). SP has significant effects on a range of important fitness-related traits in females. It significantly increases egg production and decreases female receptivity to remating (Chapman et al. 2003b; Liu and Kubli 2003), increases food uptake (Carvalho et al. 2006), alters nutrient balancing (Ribeiro and Dickson 2010), and increases the expression of antimicrobial peptides (Peng et al. 2005). It also inhibits female siesta sleep (Isaac et al. 2010), alters water balance (Cognigni et al. 2011), and is involved in regulating sperm release from the storage organs (Avila et al. 2010). The sex peptide receptor has been identi- fied, and it is expressed in the female genital tract and central nervous system (Soller et al. 2006; Yapici et al. 2008; Rezaval étal 2012).

The fitness effects of SP in males and females appear to represent hallmarks of interlocus sexual conflict (Rice 1998; Chapman et al. 2003a; Arnqvist and Rowe 2005), in that repeated receipt of SP exacerbates the survival cost of mating in females (Wigby and Chapman 2005), while simultaneously increasing a male's "per mating" offspring production (Fricke et al. 2009). It has been hypothesized that males and females are locked into a cycle of antagonistic coevolution over the phenotypic effects of SP and the female's physiological responses to it. Understanding the mechanisms underlying female genomic responses to Sfps such as SP is therefore of great interest in revealing the sophisticated chemical communication between the sexes at mating. It also rep- resents an excellent starting point to understand whole genome responses to sexual conflict and the potential role of Sfps in driving sexually antagonistic coevolution between the sexes.

Transcriptome studies have provided significant insights into the extensive genome-wide changes in gene expression that together form a synchronized response to mating and to Sfp receipt (McGraw et al. 2004; Mack et al. 2006; Domanitskaya et al. 2007 Innocenti and Morrow 2009). Such studies have also sought to characterize potential genomic signatures of sex- ual conflict (Gioti et al. 2012). To date (McGraw et al. 2004; Mack et al. 2006; Gioti et al. 2012) expression profiles have been conducted at different levels of resolution-from whole organisms (McGraw et al. 2004) to tissue-specific profiles (Mack et al. 2006)-and from total responses to mating (Mack et al. 2006), to courtship, to ejaculate receipt, and to specific Sfps (McGraw et al. …

Search by... Author
Show... All Results Primary Sources Peer-reviewed

Oops!

An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.