Project description:Pheromones exchanged by conspecifics are a major class of chemical signals that can alter behavior, physiology, and development. In particular, males and females communicate with potential mating partners via sex pheromones to promote reproductive success. Physiological and developmental mechanisms by which pheromones facilitate progeny production remain largely enigmatic. Here we describe how a C. elegans male pheromone, ascr#10, improves the oogenic germline. Before most signs of aging become evident, C. elegans hermaphrodites start producing lower quality gametes characterized by abnormal morphology, increased rates of chromosomal nondisjunction, and higher penetrance of deleterious alleles. We show that exposure to the male pheromone substantially ameliorates all of these defects and reduces embryonic lethality. ascr#10 stimulates proliferation of germline precursor cells in adult hermaphrodites. Greater precursor supply increases physiological germline cell death, which is required to improve oocyte quality in older mothers. The hermaphrodite germline is sensitive to the pheromone only during a time window, comparable in duration to a larval stage, used by the pre-reproductive adults to assess suitability of the environment for reproduction. Our results identify developmental events that occur in the oogenic germline in response to a male pheromone. They also suggest that the opposite effects of the pheromone on gamete quality and organismal longevity arise from a competition over resource allocation between soma and the germline.
Project description:The nematode Caenorhabditis elegans is an important model for studies of germ cell biology, including specification as sperm or oocyte, the meiotic cell cycle and gamete differentiation. Fundamental to those studies is a genome-level knowledge of the germline transcriptome. Here we use RNA-Seq to identify genes expressed in isolated XX gonads, which are roughly 95% germline and 5% somatic gonadal tissue. We generate data from mutants making either sperm [fem-3(q96)] or oocytes (fog-2), both grown at 22M-BM-0C. Our dataset identifies a total of 10,754 mRNAs in the polyadenylated transcriptome of XX gonads, with 1,723 enriched in spermatogenic gonads, 2,869 enriched in oogenic gonads and the remaining 6,274 not enriched in either. These spermatogenic, oogenic and gender-neutral gene datasets compare well with those of earlier studies, but double the number of genes identified. We also query our RNA-Seq data for differential exon usage and find 351 mRNAs with sex-specific isoforms. We suggest that this new dataset will prove useful for studies focusing on C. elegans germ cell biology. Comparison of spermatogenic vs oogenic transcriptomes
Project description:PUF RNA-binding proteins control stem cells in diverse species, including mammalian, arthropod, and nematode, in addition to other biological functions. The C. elegans PUF protein FBF serves as a paradigm for metazoan PUFs. FBF is essential for the maintenance of germline stem cells but also regulates the hermpahrodite sperm/oocyte cell fate switch and is critical for the process of spermatogenesis. We have attempted to “disentangle” the different roles of FBF by comparing its targets in spermatogenic and oogenic germlines. To this end, we used FBF iCLIP to learn its binding profile in an adult hermaphrodite germline that is sexually transformed and makes only sperm due to a temperature-sensitive sex-determination mutant. As a control, we analyzed FBF iCLIP data from oogenic germlines at the same temperature. Using a modified peak calling algorithm, we identified FBF binding sites in oogenic animals at 20°C, oogenic animals at 25°C, and spermatogenic animals at 25°C. Oogenic FBF targets were similar at 20°C and 25°C. By contrast, FBF mRNA targets in spermatogenetic animals had a distinct profile, revealing sperm-specific targets that are likely critical for the FBF role in spermatogenesis. Most importantly, we found FBF bound to mRNAs regardless of germline gender. In particular, a group of 22 mRNAs clustered as bound with high frequency in a gender- and temperature-independent manner. These 22 mRNAsencode RNA-binding proteins and stem cell regulators and may be crucial for the FBF role in in stem cell maintenance.
Project description:The nematode Caenorhabditis elegans is an important model for studies of germ cell biology, including specification as sperm or oocyte, the meiotic cell cycle and gamete differentiation. Fundamental to those studies is a genome-level knowledge of the germline transcriptome. Here we use RNA-Seq to identify genes expressed in isolated XX gonads, which are roughly 95% germline and 5% somatic gonadal tissue. We generate data from mutants making either sperm [fem-3(q96)] or oocytes (fog-2), both grown at 22°C. Our dataset identifies a total of 10,754 mRNAs in the polyadenylated transcriptome of XX gonads, with 1,723 enriched in spermatogenic gonads, 2,869 enriched in oogenic gonads and the remaining 6,274 not enriched in either. These spermatogenic, oogenic and gender-neutral gene datasets compare well with those of earlier studies, but double the number of genes identified. We also query our RNA-Seq data for differential exon usage and find 351 mRNAs with sex-specific isoforms. We suggest that this new dataset will prove useful for studies focusing on C. elegans germ cell biology.
Project description:Mammalian sexual reproduction relies on the dichotomy of male and female germ cell development. However, the underlying mechanisms remain unclear. Here, we show that ZGLP1, a conserved transcriptional regulator with GATA-like zinc fingers, determines the oogenic fate in mice. ZGLP1 acts downstream of bone morphogenetic protein (BMP), but not retinoic acid (RA), and is essential for the oogenic program and meiotic entry. ZGLP1 overexpression induces differentiation of in vitro primordial germ cell-like cells (PGCLCs) into fetal oocytes by activating the oogenic programs repressed by Polycomb activities, whereas RA signaling contributes to the oogenic program maturation and PGC program repression. Our findings elucidate the mechanism for mammalian oogenic fate determination, providing a foundation for promoting in vitro gametogenesis and reproductive medicine.
Project description:Mammalian sexual reproduction relies on the dichotomy of male and female germ cell development. However, the underlying mechanisms remain unclear. Here, we show that ZGLP1, a conserved transcriptional regulator with GATA-like zinc fingers, determines the oogenic fate in mice. ZGLP1 acts downstream of bone morphogenetic protein (BMP), but not retinoic acid (RA), and is essential for the oogenic program and meiotic entry. ZGLP1 overexpression induces differentiation of in vitro primordial germ cell-like cells (PGCLCs) into fetal oocytes by activating the oogenic programs repressed by Polycomb activities, whereas RA signaling contributes to the oogenic program maturation and PGC program repression. Our findings elucidate the mechanism for mammalian oogenic fate determination, providing a foundation for promoting in vitro gametogenesis and reproductive medicine.
Project description:Candida albicans can stochastically switch between two phenotypes, white and opaque. Opaque cells are the sexually competent form of C. albicans and therefore undergo efficient polarized growth and mating in the presence of pheromone. In contrast, white cells cannot mate, but are induced - under a specialized set of conditions - to form biofilms in response to pheromone. In this work, we compare the genetic regulation of such "pheromone-stimulated" biofilms with that of "conventional" C. albicans biofilms. In particular, we examined a network of six transcriptional regulators (Bcr1, Brg1, Efg1, Tec1, Ndt80, and Rob1) that mediate conventional biofilm formation for their potential roles in pheromone-stimulated biofilm formation. We show that four of the six transcription factors (Bcr1, Brg1, Rob1, and Tec1) promote formation of both conventional and pheromone-stimulated biofilms, indicating they play general roles in cell cohesion and biofilm development. In addition, we identify the master transcriptional regulator of pheromone-stimulated biofilms as C. albicans Cph1, ortholog of Saccharomyces cerevisiae Ste12. Cph1 regulates mating in C. albicans opaque cells, and here we show that Cph1 is also essential for pheromone-stimulated biofilm formation in white cells. In contrast, Cph1 is dispensable for the formation of conventional biofilms. The regulation of pheromone- stimulated biofilm formation was further investigated by transcriptional profiling and genetic analyses. These studies identified 206 genes that are induced by pheromone signaling during biofilm formation. One of these genes, HGC1, is shown to be required for both conventional and pheromone-stimulated biofilm formation. Taken together, these observations compare and contrast the regulation of conventional and pheromone-stimulated biofilm formation in C. albicans, and demonstrate that Cph1 is required for the latter, but not the former.
Project description:Candida albicans can stochastically switch between two phenotypes, white and opaque. Opaque cells are the sexually competent form of C. albicans and therefore undergo efficient polarized growth and mating in the presence of pheromone. In contrast, white cells cannot mate, but are induced - under a specialized set of conditions - to form biofilms in response to pheromone. In this work, we compare the genetic regulation of such "pheromone-stimulated" biofilms with that of "conventional" C. albicans biofilms. In particular, we examined a network of six transcriptional regulators (Bcr1, Brg1, Efg1, Tec1, Ndt80, and Rob1) that mediate conventional biofilm formation for their potential roles in pheromone-stimulated biofilm formation. We show that four of the six transcription factors (Bcr1, Brg1, Rob1, and Tec1) promote formation of both conventional and pheromone-stimulated biofilms, indicating they play general roles in cell cohesion and biofilm development. In addition, we identify the master transcriptional regulator of pheromone-stimulated biofilms as C. albicans Cph1, ortholog of Saccharomyces cerevisiae Ste12. Cph1 regulates mating in C. albicans opaque cells, and here we show that Cph1 is also essential for pheromone-stimulated biofilm formation in white cells. In contrast, Cph1 is dispensable for the formation of conventional biofilms. The regulation of pheromone- stimulated biofilm formation was further investigated by transcriptional profiling and genetic analyses. These studies identified 206 genes that are induced by pheromone signaling during biofilm formation. One of these genes, HGC1, is shown to be required for both conventional and pheromone-stimulated biofilm formation. Taken together, these observations compare and contrast the regulation of conventional and pheromone-stimulated biofilm formation in C. albicans, and demonstrate that Cph1 is required for the latter, but not the former. 4 condition experiment: white and opaque cells in planktonic and pheromone-induced biofilm conditions with and without alpha pheromone. WT strain (P37005), the tec1 mutant strain and the cph1 mutant strain