Mutations in the binding sites depress the enhancer activities of <i>Tokudaia</i> TESCO.

<p>Mutated TESCO, in which all binding sites were replaced by mouse sequence, showed recovery of activities by co-transfection of TMU_SOX9 and SF1. However, no significant activity was observed by TMU_SRY. Means and standard deviations from at least three independent experiments are shown. *<i>P</i><0.05.</p

Impaired transcription factor function of <i>T. muenninki</i> SRY.

<p>(A) Comparison of the enhancer activity of mouse TESCO by co-transfecting mSRY with SF1 and TMU_SRY with SF1. <i>T. muenninki</i> SRY did not increase the activity of mouse TESCO. (B) One amino acid substitution at the 21st position within HMG-box had no effect on the function of <i>T. muenninki</i> SRY. The TMU_SRY_StoA also did not increase the activity of mouse TESCO. Means and standard deviations from at least three independent experiments are shown.</p

Evolution of the Y chromosome and sex-determining mechanism in the genus <i>Tokudaia</i>.

<p>Nucleotide substitutions accumulated in SRY and SF1 binding sites in TESCO of the common ancestor after emergence of a new sex-determining gene, leading to inactivation of TESCO, and SRY could not function as a transcription factor. In the common ancestor or in a lineage of <i>T. muenninki</i>, SRY itself lost function caused by mutations in the <i>SRY</i> sequence. Neo-X and neo-Y chromosomes were acquired by fusion of a pair of autosomes with the X and Y chromosomes. Many pseudo SRY copies amplified and were distributed throughout the heterochromatic region in the neo-Y chromosome. In a common ancestor of <i>T. osimensis</i> and <i>T. tokunosimensis</i>, a part of the Y region translocated to the distal region of X chromosome and the remaining Y chromosome region containing <i>SRY</i> (and other genes) was completely lost.</p

The identity of TESCO sequences.

<p>The identity of TESCO sequences.</p

L'Alerte : journal indépendant : politique, littéraire et commercial

11 mai 19081908/05/11 (A12)-1908/05/11

<i>In Vivo</i> Function and Evolution of the Eutherian-Specific Pluripotency Marker UTF1

<div><p>Embryogenesis in placental mammals is sustained by exquisite interplay between the embryo proper and placenta. <i>UTF1</i> is a developmentally regulated gene expressed in both cell lineages. Here, we analyzed the consequence of loss of the <i>UTF1</i> gene during mouse development. We found that homozygous <i>UTF1</i> mutant newborn mice were significantly smaller than wild-type or heterozygous mutant mice, suggesting that placental insufficiency caused by the loss of <i>UTF1</i> expression in extra-embryonic ectodermal cells at least in part contributed to this phenotype. We also found that the effects of loss of <i>UTF1</i> expression in embryonic stem cells on their pluripotency were very subtle. Genome structure and sequence comparisons revealed that the <i>UTF1</i> gene exists only in placental mammals. Our analyses of a family of genes with homology to UTF1 revealed a possible mechanism by which placental mammals have evolved the <i>UTF1</i> genes.</p></div

The <i>UTF1</i> gene is present only in the genomes of eutherian (placental) mammals.

<p>(A) Genomic organizations surrounding the <i>UTF1</i> locus in mammals and their corresponding genomic regions in other organisms. Black boxes indicate regions without available genomic sequences. (B) VISTA Browser (VGB2.0) plot of the 65.5 kb interval (ch10∶134,506,934-134,572,432) containing <i>KNDC1</i>, <i>UTF1</i> and <i>VENTX</i> genes in the human genome. Conservation plots for elephant (top panel) mouse (second panel), opossum (third panel) and wallaby (bottom panel), with respect to human, are shown in the coordinates of the human sequence (horizontal axis). Dark blue boxes indicate portions with unavailable DNA sequences in the database.</p

Role of UTF1 in the placenta.

<p>(A) Immunohistochemical analyses of UTF1 protein expression in wild-type placentas at 12.5 and 14.5 dpc. LB, labyrinth layer. (B) H&E-stained sections of <i>UTF1</i> heterozygous and homozygous mutant placentas. The boundary between the LB region and others is indicated by the dotted line. Each column of bar graph represents the mean of placenta weight with standard deviation (SD) (n = 3). *, p<0.05; **, p<0.01. (C) Cells in the mitotic phase in <i>UTF1</i> homozygous and heterozygous mutant placentas at 12.5 dpc visualized by immunostaining with an anti-phospho-histone H3 (Ser10) antibody. Phospho-histone H3-positive mitotic cells are marked by white arrowheads. Cells were counterstained with 4′,6′ diamidino-2-phenylindole (DAPI). Each column of bar graph represents the mean of number of phosphorylated histone H3 in 0.1 mm square with SD (n = 3). *, p<0.05. (D) Magnified view of H&E-stained sections of placentas. Placentas with the indicated genotypes were sectioned and stained. Dc, deciduas; Gly, glycogen trophoblast; TGC, trophoblast giant cell; Sp, spongiotrophoblast.</p

Implication of derivation of <i>UTF1</i> from <i>ZCSAN20-like</i> in an ancestor of placental mammals.

<p>(A) Diagram showing the domain structure of ZCSAN20-like protein with the amino acid sequence (1–867). Triangles with numbers indicate positions corresponding to exon-intron boundaries of the gene encoding ZCSAN20-like protein. Brown and black bars indicate positions with significant similarity to UTF1, which are shown in B and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0068119#pone.0068119.s006" target="_blank">Figure S6</a>, respectively. (B) Alignment of the amino acid sequence of the SANT domain of human UTF1 with that of ZSCAN20-like protein. Amino acid identity and similarity between UTF1 and ZSCAN20-like are marked by double and single dots, respectively. (C) A neighbor-joining tree analysis was constructed based on the number of nucleotide differences per site. The bootstrap value supporting each internal branch is indicated at the node. A cluster containing UTF1s and opossum ZSCAN20-like is boxed with a red line. (D) Model of <i>UTF1</i> evolution in a common ancestor of eutherian (placental) mammals after divergence which separates from marsupials. Data in B, C, and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0068119#pone.0068119.s006" target="_blank">Figure S6</a> suggest that the <i>UTF1</i> gene was derived from a portion of the <i>ZCAN20-like</i> gene. After this transition, extensive nucleotide sequence changes occurred to evolve the <i>UTF1</i> gene, which eliminated the trace of homology between UTF1 and ZSCAN20-like except for two regions including their SANT domains. However, the depicted panel is just one possibility. For example, regions without similarity to the <i>ZCAN20-like</i> gene (depicted with a red rectangle) could have arisen <i>de novo</i> by modification of the sequences that had been present before translocation of the <i>ZCAN20-like</i> gene. The second SANT domain of ZSCAN20-like and its possible derivative in UTF1 are indicated by a brown bold line, while regions corresponding to those shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0068119#pone.0068119.s006" target="_blank">Figure S6</a> are marked by a black line.</p

Phenotypes of <i>UTF1</i> homozygous mutant mice with a mixed genetic background of C57BL/6J (25%) and ICR (75%).

<p>(A) Weight of viable <i>UTF1</i> homozygous mutant mice generated by intercrossing heterozygous mutant mice that had been backcrossed twice with wild-type ICR mice. These analyses revealed that adult <i>UTF1</i> homozygous mutant mice (4-weeks-old) were viable, but significantly smaller than corresponding wild-type and heterozygous mutant mice. Data represent the mean with SD (n = 4). **, p<0.01. (B) Intercrosses between <i>UTF1</i> homozygous and heterozygous mutant mice. These intercrosses showed that the <i>UTF1</i> homozygous mutation with a mixed mouse genetic background did not affect fertility, but led to the generation of small mice. Mouse weights were examined at 4 weeks after birth. Data represent the mean with SD (n = 4). *, p<0.05;</p