29 Matching Annotations
  1. Jul 2019
    1. KDM6B (also called JMJD3) is a histone demethylase that specifically demethylates H3K27me3 and is involved in transcriptional activation during normal development

      KDM6B activation of genes critical for early developmental processes, such as gonad specification and body patterning.

    2. Recently, epigenetic marks, such as DNA methylation and histone modifications of known regulators of gonadal differentiation, have been shown to differ between temperatures in species with temperature-dependent sex determination

      Methylation, or the addition of methyl groups to cytosines on DNA often leads to silencing of genes.

      Female-producing temperatures specifically lead to de-methylation and addition of activating histone marks to the promoter for the gene encoding the enzyme that produces estrogen in turtles, alligators, and sea bass.

    3. Trimethylation of H3K27 contributes to transcriptional repression in many organisms

      H3K27me3 is a histone mark that recruits repressive factors to that region of DNA, essentially silencing any local gene expression.

    4. We previously sequenced the T. scripta gonadal transcriptome during developmental stages 15 to 21 at male-producing (26°C) and female-producing (32°C) temperatures and found that Kdm6b was up-regulated at 26°C

      The authors originally sequenced the turtle embryos at male- and female-producing temperatures to identify differences in gene expression that drive sex development.

      Kdm6b was one of six genes consistently upregulated at male-producing temperatures. KDM6B was likely chosen for a follow-up study due to its potential to regulate the expression of multiple male development genes.

    5. In many reptiles, including the red-eared slider turtle Trachemys scripta elegans (T. scripta), gonadal sex is determined by the environmental temperature experienced during embryogenesis

      As opposed to the genome conferring sex as it does in vertebrates (e.g. XX confer female development and XY leads male development in many mammals), the ambient environment determines sex for some organisms.

      In most reptiles, as well as some amphibians and fish, the incubation temperature of eggs directly determines whether males or females will hatch.

  2. Jun 2019
    1. dimorphic

      Dimorphic indicates differences in characteristics between males and females of the same species other than the sex cells.

    2. gonad

      Gonad refers the organ that produces an organism's reproductive cells.

      For mammals, this is the testis in males and ovary in females.

    3. transcription

      The creation of an RNA transcript from DNA.

    4. aromatase

      An enzyme that produces estrogen, the main female sex hormone.

    5. intron retention

      A transcription event in which introns, which are frequently excluded from mRNA, are instead maintained in the mRNA transcript.

      Intron retention allows for more diversity of mRNA transcripts from the same DNA.

  3. May 2019
    1. catalysis

      Catalysis is the initiation and acceleration of a chemical reaction.

      In this case, the authors point to KDM6B as the catalyst for Dmrt1 expression and thus male sex development.

    2. morphology

      Morphology describes biological structures.

    3. meiotic

      Relating to cell division that gives rise to sex cells.

    4. histone H3 lysine 27 (H3K27) demethylase KDM6B

      DNA is wrapped around proteins called histones for the organization and compaction of eukaryotic genomes.

      The proteins that make up histones have multi-peptide "tails" that can be modified by small chemical groups like methyl or acetyl additions. These groups are added or removed by specific proteins, such as KDM6B.

    5. ectopic

      Ectopic describes events occurring in locations that do not naturally have such events.

      For example, expression of a brain-specific gene in a toenail would be considered ectopic gene expression.

    6. testicular Sertoli cell

      Male sex cells that are required to form testes and sperm.

    7. primordial germ cells

      Progenitor sex cells that go on to make all the reproductive cells in an organism.

  4. Feb 2019
    1. RNA interference (RNAi)

      RNAi describes the process in which RNA molecules target and degrade messenger RNA molecules to block protein expression.

      shRNAs are one type of RNA that is used for RNAi.

    2. in ovo

      In ovo refers to the delivery of molecules directly to the embryo.

      In this experiment, the authors have found a way to inject the shRNAs directly into the embryos through the egg.

    3. short hairpin RNAs

      Short hairpin RNAs are small RNA molecules that form a tight looping "hairpin" structure.

      These RNAs target complementary messenger RNA molecules for degradation, effectively silencing protein expression of its target RNA.

    4. master regulator

      A master regulator often refers to a protein initiates expression of all genes involved in a specific pathway, such as cell fate pathways like testes development.

    5. gonad-mesonephros complexes

      These complexes are the earliest sites of gonad development.

    6. seminiferous cords

      Seminiferous cords are one of the earliest male-specific tissues formed in the gonad development. These cords ultimately develop into tubules which hold sperm.

    7. germ cells

      Germ cells are an organism's reproductive cells, or the cells that go on to make gametes, like sperm and eggs.

    8. phenotypic plasticity

      A phenotype describes the observable physical properties of an organism. Likewise, a genotype defines the genetic composition of an organism.

      Phenotypic plasticity is the ability of a single genotype to produce multiple phenotypes.

    9. somatic cells

      All cells in an organism other than the reproductive cells.

    10. DNA methylation

      Methyl groups can be added to cytosine nucleotides of DNA. Often, genomic regions with high DNA methylation are associated with the silencing of gene expression.

    11. epigenetic

      Epigenetic indicates a heritable change in gene expression that does not change DNA sequence.

    12. promoter

      A promoter is a region of DNA associated with transcription initiation.