Project description:In plants, multiple lineages have evolved sex chromosomes independently, providing a powerful comparative framework, but few specific determinants controlling the expression of a specific sex have been identified. We investigated sex-determinants in Caucasian persimmon, Diospyros lotus, a dioecious plant with heterogametic males (XY). Male-specific short nucleotide sequences were used to define a male determining region. A combination of transcriptomics and evolutionary approaches detected a Y-specific sex-determinant candidate, OGI, that displays male-specific conservation among Diospyros species. OGI encodes a small RNA targeting the autosomal MeGI gene, a homeodomain transcription factor regulating anther fertility in dosage-dependent fashion. This identification of a feminizing gene suppressed by a Y-chromosome-encoded small RNA contributes to our understanding of the evolution of sex chromosome systems in higher plants.
Project description:In plants, multiple lineages have evolved sex chromosomes independently, providing a powerful comparative framework, but few specific determinants controlling the expression of a specific sex have been identified. We investigated sex-determinants in Caucasian persimmon, Diospyros lotus, a dioecious plant with heterogametic males (XY). Male-specific short nucleotide sequences were used to define a male determining region. A combination of transcriptomics and evolutionary approaches detected a Y-specific sex-determinant candidate, OGI, that displays male-specific conservation among Diospyros species. OGI encodes a small RNA targeting the autosomal MeGI gene, a homeodomain transcription factor regulating anther fertility in dosage-dependent fashion. This identification of a feminizing gene suppressed by a Y-chromosome-encoded small RNA contributes to our understanding of the evolution of sex chromosome systems in higher plants. For expression analyses, mixed buds were sampled on June 17, and July 4, 2013, corresponding to the early differentiation stages of male/female primordia, respectively.
Project description:Long-term memory formation is dependent on gene expression changes in the hippocampal region of the brain. Aging-related memory impairments and incidence of pathological memory disorders such as Alzheimer’s disease differ between males and females, and yet little is known about how aging-related changes to the transcriptome and chromatin environment differs between sexes in the hippocampus. To investigate this question, we compared the chromatin accessibility landscape and gene expression/alternative splicing pattern of young adult and aged mouse hippocampus of both males and females using ATAC-seq and RNA-seq. We detected significant aging-dependent changes in the expression of genes involved in immune response, cell adhesion, and synaptic function, and aging-dependent changes in the alternative splicing of myelin sheath genes. We found significant sex-bias in the expression and alternative splicing of hundreds of genes, including aging-dependent female-biased expression of myelin sheath genes and aging-dependent male-biased expression of genes involved in synaptic activity. Aging was associated with increased chromatin accessibility in both male and female hippocampus, especially in repetitive elements, and with an increase in LINE1 transcription. We detected significant sex-bias in chromatin accessibility in both autosomes and the X chromosome, with male-biased accessibility enriched at promoters and CpG-rich regions. Overall, sex differences in both gene expression and chromatin accessibility were amplified with aging, revealing that although some aspects of hippocampal aging are sex-independent, underlying sex differences in gene expression and chromatin dynamics in aging may shed light on sex differences in aging-related and pathological memory loss.
Project description:In UV sexual systems, sex is determined during the haploid phase of the life cycle and males have a V chromosome whereas females have a U chromosome. Previous work in the model Ectocarpus revealed that the V chromosome has a dominant role in male sex determination and the female developmental program being a ‘default’ program, triggered in the absence of the male master sex determination gene(s). Here, we describe the identification of a genetically male giant kelp strain presenting phenotypic features typical of a female, despite lacking the U-specific region. The conversion to the female developmental program is however incomplete, because gametes of this feminised male are unable to produce the sperm-attracting pheromone lamoxiren. We identify the transcriptomic pathways underlying the male and female specific developmental programs and show that the phenotypic feminisation of the variant strain is associated with both feminisation and de-masculinisation of gene expression patterns. Importantly, the feminisation phenotype was associated with the dramatic downregulation of two V-specific genes including a candidate sex-determining gene on the V-specific region. Our results reveal the transcriptional changes associated with sexual differentiation in a UV system with extensive sexual dimorphism, disentangling the role of sex-linked genes and autosomal gene expression in the initiation of the male and female developmental programs. Overall, the data presented here imply that the U-specific region in the giant kelp is not required to initiate the female developmental program, but is critical to produce fully functional eggs, arguing against the idea that female is the ‘default’ sex in this species.
Project description:Fibrosis is a common pathway in the progression of chronic kidney disease. Extracellular matrix deposition from myofibroblasts causes scarring, tissue stiffness and organ failure. This submission studies the role of Sex determining region Y-box 9 (SOX9) in kidney fibrosis.