Project description:Background: Modifications to early development can lead to evolutionary diversification. The early stages of development are under maternal control, as mothers produce eggs loaded with nutrients, proteins and mRNAs that direct early embryogenesis. Maternally provided mRNAs are the only expressed genes in initial stages of development and are tightly regulated. Differences in maternal mRNA provisioning could lead to phenotypic changes in embryogenesis and ultimately evolutionary changes in development. However, the extent that maternal mRNA expression in eggs can vary is unknown for most developmental models. Here, we use a species with dimorphic development— where females make eggs and larvae of different sizes and life-history modes—to investigate the extent of variation in maternal mRNA provisioning to the egg. Results: We find that there is significant variation in gene expression across eggs of different development modes, and that there are both qualitative and quantitative differences in mRNA expression. We separate parental effects from allelic effects, and find that both mechanisms contribute to mRNA expression differences. We also find that offspring of intraspecific crosses differentially provision their eggs based on the parental cross direction (a parental effect), which has not been previously demonstrated in reproductive traits like oogenesis. Conclusion: We find that maternally controlled initiation of development is functionally distinct between eggs of different sizes and maternal genotypes. Both allele-specific effects and parent-of-origin effects contribute to gene expression differences in eggs. The latter indicates an intergenerational effect where a parent’s genotype can affect gene expression in an egg made by the next generation.
2023-04-19 | GSE225230 | GEO
Project description:Demographic and seasonal variation in the cloacal microbiome of free-ranging striped plateau lizards, Sceloporus virgatus
Project description:Maternal inheritance of mitochondrial DNA (mtDNA) is highly conserved in metazoans. While many species eliminate paternal mtDNA during late sperm development to foster maternal inheritance, the regulatory mechanisms governing this process remain elusive. Through a large-scale genetic screen in Drosophila, we identified 47 mutant lines exhibiting substantial retention of mtDNA in mature sperm. We mapped one line to Poldip2, a gene predominantly expressed in the testis. Disruption of Poldip2 led to pronounced mtDNA retention in mature sperm and subsequent paternal transmission to progeny. Further investigation via imaging, biochemical analyses and ChIP assays revealed that POLDIP2 is a mitochondrial matrix protein capable of binding to mtDNA. Moreover, we uncovered that CLPX, a key component of the major mitochondrial protease, binds to POLDIP2 to co-regulate mtDNA elimination in Drosophila spermatids. This study shed light on the mechanisms underlying mtDNA removal during spermatogenesis, underscoring the pivotal role of this process in safeguarding maternal inheritance.
Project description:Maternal stress, anxiety, and depression increase the risk of psychiatric disorders in the progeny. These maternal effects can extend beyond the first generation and affect the grandchildren. In contrast to paternal, maternal effects can impact the offspring not only during gametogenesis, but also through fetal and early-postnatal life, increasing phenotypic complexity and the overall impact. To better understand its non-genetic structure, we dissected a complex maternally-transmitted phenotype to elementary behaviors and their corresponding transmission mechanisms. Chronic stress and depression are associated with reduced serotonin1A receptor (5-HT1AR) levels, and we reported that 5-HT1AR+/- dams transmit anxiety/stress-reactivity traits to their wild-type offspring. Here we show that the maternal effect is propagated to multiple generations, and that the behavioral traits are not transmitted in unison, but rather via parallel and segregated mechanisms, each with generation-dependent penetrance and gender specificity. The ârisk-avoidanceâ and âhypoactivityâ traits of anxiety were transmitted, via a neuro-immune pathway, consecutively from mother to the wild-type F1, F2, and occasionally F3 generation by iterative non-gametic-programming, while the âincreased stress-reactivityâ trait was transmitted to the F2 generation by gametic-programming. Iterative non-gametic-programming of anxiety was linked, via gene expression changes and clustered DNA hypo/hypermethylation at intragenic enhancers, to sphingolipid metabolism and GPCRs in the F1/F2 hippocampus, suggesting dysregulated lipid raft functioning/transmembrane signaling. Conversely, gametic-programming of behavior was predominantly associated with hypomethylation at different promoter-enhancing sequences within a set of genes with diverse neuronal functions. Since differential methylation appeared only postnatally in F2 neurons and was absent in F3 neurons, it is secondary to earlier F2 gametic changes that survive reprogramming in the early embryo, but are erased in F3 germ-cells. Our data introduce parallel and segregated non-genetic transmission of traits as a mechanism that may explain the propagation and pleiotropy of complex behavioral and psychiatric disease phenotypes across generations. Compared three generations of male offspring from wild-type and 5HT1A-R-/+ Swiss Webster mothers with two replicates per sample. Included as well is F2 embryo transfer from wild-type and het parents in wild-type surogates
Project description:Here we present the first characterisation of small RNAs in honey bee reproductive tissues. We conclude that small RNAs are likely to play an integral role in honey bee gametogenesis and reproduction and provide a plausible mechanism for parent-of origin-effects on gene expression and reproductive physiology. present in honey bee reproductive tissues: ovaries, spermatheca, semen, fertilised and unfertilised eggs, and testes.
Project description:“Dysbiosis" of the maternal gut microbiome, in response to environmental challenges such as infection, altered diet and stress during pregnancy, has been increasingly associated with abnormalities in offspring brain function and behavior. However, whether the maternal gut microbiome regulates neurodevelopment in the absence of environmental challenge remains unclear. In addition, whether the maternal microbiome exerts such influences during critical periods of embryonic brain development is poorly understood. Here we investigate how depletion, and selective reconstitution, of the maternal gut microbiome influences fetal neurodevelopment in mice. Embryos from antibiotic-treated and germ-free dams exhibit widespread transcriptomic alterations in the fetal brain relative to conventionally-colonized controls, with reduced expression of several genes involved in axonogenesis. In addition, embryos from microbiome-depleted mothers exhibit deficient thalamocortical axons and impaired thalamic axon outgrowth in response to cell-extrinsic guidance cues and growth factors. Consistent with the importance of fetal thalamocortical axonogenesis for shaping neural circuits for sensory processing, restricted depletion of the maternal microbiome from pre-conception through mid-gestation yields offspring that exhibit tactile hyposensitivity in select sensorimotor behavioral tasks. Gnotobiotic colonization of antibiotic-treated dams with a limited consortium of spore-forming bacteria indigenous to the gut microbiome prevents abnormalities in fetal brain gene expression, fetal thalamocortical axonogenesis and adult tactile sensory behavior associated with maternal microbiome depletion. Metabolomic profiling reveals that the maternal microbiota regulates levels of numerous small molecules in the maternal serum as well as the brains of fetal offspring. Select microbiota-dependent metabolites – trimethylamine N-oxide, 5-aminovalerate, imidazole propionate, and hippurate – sufficiently promote axon outgrowth from fetal thalamic explants. Moreover, maternal supplementation with the metabolites during early gestation abrogates deficiencies in fetal thalamocortical axons and prevents abnormalities in tactile sensory behavior in offspring from microbiome-depleted dams. Altogether, these findings reveal that the maternal gut microbiome promotes fetal thalamocortical axonogenesis and select tactile sensory behaviors in mice, likely by signaling of microbially modulated metabolites to neurons in the developing brain.
Project description:In our study, differential male nucleus events and development behaviors were revealed from the fertilized eggs in response to the sperm from males of genotypic sex determination (GSD) and temperature-dependent sex determination (TSD) in gibel carp. When the eggs of maternal fish were fertilized by the sperm from males of GSD, the fertilized egg encountered similar sexual reproduction events and behaviors. However, when the eggs of maternal fish were fertilized by the sperm from males of TSD, a typical process of gynogenesis was observed. To reveal the underlying molecular mechanism of differential sperm nucleus development behaviors in the fertilized eggs, iTRAQ-based quantitative semen proteomics were performed on three semen samples from three males of GSD and three semen samples from three males of TSD respectively.
Project description:Good quality or developmentally competent eggs result in high survival of progeny. Previous research has shed light on factors that determine egg quality, however, large gaps remain. Initial development of the embryo relies on maternally-inherited molecules, such as transcripts, deposited in the egg, thus, they would likely reflect egg quality. We performed microarray analysis on zebrafish fertilized eggs of different quality from unrelated, wildtype couples to obtain a global portrait of the egg transcriptome to determine its association with developmental competence and to identify new candidate maternal-effect genes. Fifteen of the most differentially expressed genes (DEGs) were validated by quantitative real-time PCR. Gene ontology analysis showed that enriched terms included ribosomes and translation. In addition, statistical modeling using partial least squares regression and genetics algorithm also demonstrated that gene signatures from the transcriptomic data can be used to predict reproductive success. Among the validated DEGs, otulina and slc29a1a were found to be increased in good quality eggs and to be predominantly localized in the ovaries. CRISPR/Cas9 knockout mutants of each gene revealed remarkable subfertility whereby the majority of their embryos were unfertilizable.Our novel findings suggested that even in varying quality of eggs due to heterogeneous causes from unrelated wildtype couples, gene signatures exist in the egg transcriptome, which can be used to predict developmental competence. Further, transcriptomic profiling revealed two new potential maternal-effect genes that have essential roles in vertebrate reproduction.
Project description:The transgenerational maternal effects of PCOS in female progeny have been revealed. As there are evidence that a male equivalent of PCOS may exist, we asked whether sons born to mother with PCOS (PCOS-sons) transmit reproductive and metabolic phenotypes to their male progeny. Here, in a Swedish nationwide register-based cohort and a clinical case-control study from Chile we found that PCOS-sons are more often obese and dyslipidemic. Their serum miRNAs are found to potentially regulate PCOS-risk genes. Our prenatal androgenized PCOS-like mouse model with or without diet-induced obesity confirmed that reproductive and metabolic dysfunctions in F1 male offspring are passed down to F3. Small non-coding RNAs (sncRNAs) sequencing of F1-F3 sperm revealed distinct differentially expressed (DE) sncRNAs across generations in the androgenized, obese, and obese and androgenized lineages, respectively. Notably, common targets between transgenerational DEsncRNAs in mouse sperm and in PCOS-sons serum indicate similar effects of maternal hyperandrogenism. These findings strengthen the translational relevance highlighting a previously underappreciated risk of reproductive and metabolic dysfunction via the male germline transmission and potential molecular markers to study in future generations.