...Mariko Kikuchi; Miyo Yoshimoto; Tokiro Ishikawa; Yuto Kanda; Kazutoshi Mori; Toshiya Nishimura; Minoru Tanaka ABSTRACT Gametogenesis is the process through which germ cells differentiate into sexually dimorphic gametes, eggs and sperm. In the teleost fish medaka ( Oryzias latipes ), a germ cell...

... approaches. We demonstrate the applicability of the inception concept in medaka ( Oryzias latipes ) in three settings: loss of function, by introducing a pre-termination STOP codon in the open reading frame of oca2 ; locally confined multi-codon changes to generate allelic variants with different phenotypic...

... are often fatal. Consequently, congenital disorders of glycosylation (CDG) in human are rare. We modelled a putative hypomorphic mutation described in an alpha-1,3/1,6-mannosyltransferase (ALG2) index patient (ALG2-CDG) to address the developmental consequences in the teleost medaka ( Oryzias latipes ). We...

... in the neuroretina of medaka fish ( Oryzias latipes ), a well-studied system with which to address vertebrate organ growth. We reveal that a central growth regulator, Igf1 receptor (Igf1r), is necessary and sufficient for proliferation control in the postembryonic retinal stem cell niche: the ciliary marginal zone...

... genetic programs that can interact with each other during embryogenesis. Here, we have taken advantage of the different span of embryonic development between two distantly related teleosts, zebrafish ( Danio rerio ) and medaka ( Oryzias latipes ) (3 and 9 days, respectively), to explore modularity...

... of the brain in this process is not well clarified. In the present work, we investigated the mRNA levels of corticotropin-releasing hormone b ( crhb ) and its receptors ( crhr1 and crhr2 ), and found that they were upregulated at HT during the crucial period of gonadal sex determination in medaka. In order...

... specification in progenitors that exit the stem cell niche in the ciliary marginal zone (CMZ). The proper cell-type composition arising from those progenitors is a prerequisite for retinal function. Our findings in the teleost medaka ( Oryzias latipes ) uncover that the Notch-Atoh7 axis continuously patterns...

... lineages, its role in non-mammalian bone formation remains elusive. Here, we show that an osx mutation in medaka results in severe bone defects and larval lethality. Pre-osteoblasts fail to differentiate leading to severe intramembranous and perichondral ossification defects. The notochord sheath...

... gastrointestinal tract of the teleost medaka ( Oryzias latipes ). X-ray microcomputed tomography shows a correlation of 3D topography with the functional domains. Analysis of ISCs in proliferation assays and via genetically encoded lineage tracing highlights a stem cell niche in the furrow between the long...

... is sufficient to drive cell cycle re-entry and proliferation, followed by the formation of neurogenic clusters and de novo neurogenesis. Müller glia Atoh7 Medaka Retina LexPR system Lineage tracing Most adult animals show some degree of ability to regenerate lost cell types, tissues...

... after embryonic development and following their descendants. Recently, transplantation experiments involving permanently labeled cells revealed multipotent neural stem cells (NSCs) of embryonic origin in the medaka retina. To analyze whether NSC potency is affected by developmental progression...

... In vertebrates that have been examined to date, the sexual identity of germ cells is determined by the sex of gonadal somatic cells. In the teleost fish medaka, a sex-determination gene on the Y chromosome, DMY / dmrt1bY , is expressed in gonadal somatic cells and regulates the sexual identity of germ cells...

... modification maps from both pluripotent cells and mature organs of medaka fish and compared the profiles with those of human ES cells. We found that a subset of hypomethylated domains harbor H3K27me3 (K27HMDs) and their size positively correlates with the accumulation of H3K27me3. Large K27HMDs are conserved...

... organ architecture, morphology and proliferation. We found that mutations of the guanine nucleotide exchange factor ArhGEF18 affect apicobasal polarity of the retinal neuroepithelium in medaka fish. We show that ArhGEF18 -mediated activation of the small GTPase RhoA is required to maintain apicobasal...

.... Previously, we have shown that the gene encoding the type II anti-Müllerian hormone receptor, amhrII , is responsible for excessive germ cell proliferation and male-to-female sex reversal in the medaka hotei mutant. In this study, functional analyses in cultured cells and of other amhrII mutant alleles...

... their common complex expression pattern remain to be elucidated. Here we performed a pilot screen on 560 genes of the vertebrate model system medaka ( Oryzias latipes ) to systematically identify synexpression groups and investigate their regulatory properties by searching for common regulatory cues. We find...

... factors (TFs). Paradoxically, some of these factors are widely expressed in the forebrain, which raises the question of how they can mediate regional differences. To address this issue, we focused on the homeobox TF Six3.2 . With genomic and functional approaches we demonstrate that, in medaka fish...

... in the medaka model. We generated transgenic medaka lines that express GFP under control of the cathepsin K promoter in osteoclasts starting at 12 days post-fertilization (dpf), or Rankl together with CFP under control of a bi-directional heat-shock promoter. Using long-term confocal time-lapse imaging...

... movement of node cilia, is essential for left-right patterning in the mouse and other vertebrates. However, the identity of the pathways by which nodal flow is interpreted remains controversial as the molecular sensors of this process are unknown. In the current study, we show that the medaka left-right...

... approaches in medaka fish ( Oryzias latipes ) to characterise highly conserved regulatory enhancers responsible for Six6 expression. One of the enhancers drove gene expression in the differentiating and adult retina. A search for transcription factor binding sites, together with luciferase, ChIP assays...