Identification of co-regulated transcripts affecting male body size in Drosophila.
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ABSTRACT:
SUBMITTER: Coffman CJ
PROVIDER: S-EPMC1175973 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Almost all animals show sex differences in body size. For example, in Drosophila, females are larger than males. Although Drosophila is widely used as a model to study growth, the mechanisms underlying this male-female difference in size remain unclear. Here, we describe a novel role for the sex determination gene transformer (tra) in promoting female body growth. Normally, Tra is expressed only in females. We find that loss of Tra in female larvae decreases body size, while ectopic Tra expression in males increases body size. Although we find that Tra exerts autonomous effects on cell size, we also discovered that Tra expression in the fat body augments female body size in a non cell-autonomous manner. These effects of Tra do not require its only known targets doublesex and fruitless. Instead, Tra expression in the female fat body promotes growth by stimulating the secretion of insulin-like peptides from insulin producing cells in the brain. Our data suggest a model of sex-specific growth in which body size is regulated by a previously unrecognized branch of the sex determination pathway, and identify Tra as a novel link between sex and the conserved insulin signaling pathway.
| S-EPMC4692505 | biostudies-literature
Project description:The mating success of larger male Drosophila melanogaster in the laboratory and the wild has been traditionally been explained by female choice, even though the reasons are generally hard to reconcile. Female choice can explain this success by virtue of females taking less time to mate with preferred males, but so can the more aggressive or persistent courtships efforts of large males. Since mating is a negotiation between the two sexes, the behaviors of both are likely to interact and influence mating outcomes. Using a series of assays, we explored these negotiations by testing for the relative influence of male behaviors and its effect on influencing female courtship arousal threshold, which is the time taken for females to accept copulation. Our results show that large males indeed have higher copulation success compared to smaller males. Competition between two males or an increasing number of males had no influence on female sexual arousal threshold;-females therefore may have a relatively fixed 'arousal threshold' that must be reached before they are ready to mate, and larger males appear to be able to manipulate this threshold sooner. On the other hand, the females' physiological and behavioral state drastically influences mating; once females have crossed the courtship arousal threshold they take less time to mate and mate indiscriminately with large and small males. Mating quicker with larger males may be misconstrued to be due to female choice; our results suggest that the mating advantage of larger males may be more a result of heightened male activity and relatively less of female choice. Body size per se may not be a trait under selection by female choice, but size likely amplifies male activity and signal outputs in courtship, allowing them to influence female arousal threshold faster.
| S-EPMC4676700 | biostudies-literature
Project description:Correct scaling of body and organ size is crucial for proper development, and the survival of all organisms. Perturbations in circulating hormones, including insulins and steroids, are largely responsible for changing body size in response to both genetic and environmental factors. Such perturbations typically produce adults whose organs and appendages scale proportionately with final size. The identity of additional factors that might contribute to scaling of organs and appendages with body size is unknown. Here, we report that loss-of-function mutations in Drosophila Activin? (Act?), a member of the TGF-? superfamily, lead to the production of small larvae/pupae and undersized rare adult escapers. Morphometric measurements of escaper adult appendage size (wings and legs), as well as heads, thoraxes, and abdomens, reveal a disproportional reduction in abdominal size compared to other tissues. Similar size measurements of selected Act? mutant larval tissues demonstrate that somatic muscle size is disproportionately smaller when compared to the fat body, salivary glands, prothoracic glands, imaginal discs, and brain. We also show that Act? control of body size is dependent on canonical signaling through the transcription-factor dSmad2 and that it modulates the growth rate, but not feeding behavior, during the third-instar period. Tissue- and cell-specific knockdown, and overexpression studies, reveal that motoneuron-derived Act? is essential for regulating proper body size and tissue scaling. These studies suggest that, unlike in vertebrates, where Myostatin and certain other Activin-like factors act as systemic negative regulators of muscle mass, in Drosophila, Act? is a positive regulator of muscle mass that is directly delivered to muscles by motoneurons. We discuss the importance of these findings in coordinating proportional scaling of insect muscle mass to appendage size.
| S-EPMC6893369 | biostudies-literature
Project description:Our aim is to identify circadian transcripts that are co-regulated with [Ca2+]cyt, with the eventual goal of identifying genetic regulators and targets for circadian oscillations of [Ca2+]cyt. We have identified two conditions in which [Ca2+]cyt behaves differently to other circadian outputs. 1. Treatment of plants with nicotinamide, a metabolic inhibitor of ADPR cyclase, abolishes the circadian oscillations of [Ca 2+]cyt. However, leaf movement, CCA1, LHY, TOC1 and CAB transcript abundance and CAB promoter activity are all rhythmic albeit with a longer period (Dodd et al., 2007). 2. The toc1-1 mutant, which shortens the circadian period of all other rhythms tested, has no effect on the period of [Ca2+]cyt oscillations (Xu et al., 2007). We will measure the circadian regulation of transcript abundance in wild type (C24), toc1-1 and nicotinamide (C24)-treated plants. Method: Wild type (C24) and toc1-1 seeds were sown on 1/2MS 0.8% agar plates and imbibed at 4 C for 48 hours. Seedlings were grown in LD cycles of 12hL:12hD at 19 C for 11 days to entrain the oscillator. Following transfer to LL at dawn on the 12th day, 50% of the wild type seedlings were dosed with 50 mM nicotinamide every 2 hours over the entire course of the experiment. Wild type, toc1-1 and nicotinamide-treated seedlings (approx. 100 for each sample, excluding roots) were harvested at 4 hour intervals from 49 to 93 hours in LL (12 time points covering the entire third and fourth circadian cycles). Two independent replicates of the whole experiment will be hybridised. 72 samples were used in this experiment.
2009-12-09 | E-GEOD-19271 | biostudies-arrayexpress
Project description:Our aim is to identify circadian transcripts that are co-regulated with [Ca2+]cyt, with the eventual goal of identifying genetic regulators and targets for circadian oscillations of [Ca2+]cyt. We have identified two conditions in which [Ca2+]cyt behaves differently to other circadian outputs. 1. Treatment of plants with nicotinamide, a metabolic inhibitor of ADPR cyclase, abolishes the circadian oscillations of [Ca 2+]cyt. However, leaf movement, CCA1, LHY, TOC1 and CAB transcript abundance and CAB promoter activity are all rhythmic albeit with a longer period (Dodd et al., 2007). 2. The toc1-1 mutant, which shortens the circadian period of all other rhythms tested, has no effect on the period of [Ca2+]cyt oscillations (Xu et al., 2007). We will measure the circadian regulation of transcript abundance in wild type (C24), toc1-1 and nicotinamide (C24)-treated plants. Method: Wild type (C24) and toc1-1 seeds were sown on 1/2MS 0.8% agar plates and imbibed at 4 C for 48 hours. Seedlings were grown in LD cycles of 12hL:12hD at 19 C for 11 days to entrain the oscillator. Following transfer to LL at dawn on the 12th day, 50% of the wild type seedlings were dosed with 50 mM nicotinamide every 2 hours over the entire course of the experiment. Wild type, toc1-1 and nicotinamide-treated seedlings (approx. 100 for each sample, excluding roots) were harvested at 4 hour intervals from 49 to 93 hours in LL (12 time points covering the entire third and fourth circadian cycles). Two independent replicates of the whole experiment will be hybridised.
2009-12-10 | GSE19271 | GEO
Project description:Mushroom bodies (MBs) are the centers for olfactory associative learning and elementary cognitive functions in the Drosophila brain. As a way to systematically elucidate genes preferentially expressed in MBs, we have analyzed genome-wide alterations in transcript profiles associated with MB ablation by hydroxyurea. We selected 100 genes based on microarray data and examined their expression patterns in the brain by in situ hybridization. Seventy genes were found to be expressed in the posterodorsal cortex, which harbors the MB cell bodies. These genes encode proteins of diverse functions, including transcription, signaling, cell adhesion, channels, and transporters. Moreover, we have examined developmental functions of 40 of the microarray-identified genes by transgenic RNA interference; 8 genes were found to cause mild-to-strong MB defects when suppressed with a MB-Gal4 driver. These results provide important information not only on the repertoire of genes that control MB development but also on the repertoire of neural factors that may have important physiological functions in MB plasticity.
| S-EPMC1599978 | biostudies-literature
Project description:BackgroundDespite its important implications in behavioural and evolutionary ecology, male mate choice has been poorly studied, and the relative contribution of personality and morphological traits remains largely unknown. We used standard two-choice mating trials to explore whether two personality traits (i.e., shyness and activity) and/or body size of both sexes affect mate choice in male mosquitofish Gambusia affinis. In the first set of trials involving 40 males, we tested whether males would prefer larger females and whether the preference would be affected by males' body length and personality traits, and females' activity level. In the second set of trials (using another 40 males), we tested whether males would prefer more active females and whether the preference would be affected by males' body length and personality traits.ResultsBoth shyness and activity in males were significantly repeatable and constituted a behavioural syndrome. No overall directional preference for large (or small) females with the same activity levels was detected because larger males preferred larger females and smaller males chose smaller females. Males' strength of preference for larger females was also positively correlated with the activity level of larger females but negatively with the activity level of smaller females. Males spent more time associating with active females regardless of their body lengths, indicating males' selection was more influenced by female activity level than body size. Males' preference for inactive females was enhanced when females became active. There was no convincing evidence for the effect of males' personality traits or body length on their preferences for females' activity level.ConclusionsOur study supports the importance of body size in male mate choice but highlights that personality traits may outweigh body size preferences when males choose mating partners.
| S-EPMC8780319 | biostudies-literature
Project description:Analysis of EST and cDNA collections from a number of metazoan species has identified genes encoding long polyadenylated transcripts that do not contain ORFs of lengths typical for protein-encoding mRNAs. Noncoding functions of such polyadenylated transcripts have been elucidated in only a few examples. The corresponding genes neither contain hallmark sequence motifs nor appear to have been conserved across phyla. Thus, it is impossible to systematically identify new members of this class of gene by using sequence homology and traditional gene-finding algorithms that depend on protein-coding potential. Consequently, even their approximate number has not been established for any metazoan genome. We curated polyadenylated transcripts with limited protein-coding capacity from intergenic regions of the Drosophila melanogaster genome. We used RT-PCR assays, hybridization to RNA blots and whole-mount embryos, and computational analyses to characterize candidate transcripts. We verify the structures and expression of 17 distinct, likely non-protein-coding polyadenylated transcripts. We show that the expression of many of these transcripts is conserved in other Drosophila species, indicating that they have important biological functions.
| S-EPMC555963 | biostudies-literature
Project description:Body size is a key sexually selected trait in many animal species. If size imposes a physical limit on the production of loud low-frequency sounds, then low-pitched vocalisations could act as reliable signals of body size. However, the central prediction of this hypothesis--that the pitch of vocalisations decreases with size among competing individuals--has limited support in songbirds. One reason could be that only the lowest-frequency components of vocalisations are constrained, and this may go unnoticed when vocal ranges are large. Additionally, the constraint may only be apparent in contexts when individuals are indeed advertising their size. Here we explicitly consider signal diversity and performance limits to demonstrate that body size limits song frequency in an advertising context in a songbird. We show that in purple-crowned fairy-wrens, Malurus coronatus coronatus, larger males sing lower-pitched low-frequency advertising songs. The lower frequency bound of all advertising song types also has a significant negative relationship with body size. However, the average frequency of all their advertising songs is unrelated to body size. This comparison of different approaches to the analysis demonstrates how a negative relationship between body size and song frequency can be obscured by failing to consider signal design and the concept of performance limits. Since these considerations will be important in any complex communication system, our results imply that body size constraints on low-frequency vocalisations could be more widespread than is currently recognised.
| S-EPMC3577745 | biostudies-literature
Project description:In species with internal fertilization, sperm, and seminal fluid are transferred from male to female during mating. While both sperm and seminal fluid contain various types of molecules, including RNA, the role of most of these molecules in the coordination of fertilization or in other possible functions is poorly understood. In Drosophila, exosomes from the accessory gland, which produces seminal fluid, are transferred to females, but their potential cargoes have not been described. Moreover, while the RNA composition of sperm has been described in several mammalian species, little work on this problem has occurred in Drosophila. Here we use single nucleotide polymorphism differences between males and females from a set of highly inbred lines of D. melanogaster, and transcriptome data from the female reproductive tract, sperm, testis, and accessory gland, to investigate the potential origin, male vs female, RNA molecules isolated from 3 female reproductive tract organs, the seminal receptacle and spermatheca, which store sperm, and the parovaria, which does not. We find that mated females carry male-derived transcripts from many genes, including those that are markers of the accessory gland and known seminal fluid proteins. Our observations also support the idea that intact sperm transcripts can be isolated from the female sperm storage organs.
| S-EPMC10627254 | biostudies-literature