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Fig. 1. Zygotic VegT is the Xenopus ortholog of the VegT/Spadetail gene subfamily. (A) Phylogenetic tree of the T-box gene family associated with vertebrate mesoderm development. The phylogenetic tree was calculated by MacVector 7.2.3 software. Human Tbx6 splicing variant1 (GenBank accession no. NM_004608), human Tbx6 splicing variant2 (GenBank accession no. NM_080758), human Brachyury (T) (GenBank accession no. NM_003181), human Eomesodermin (GenBank accession no. NM_003181), mouse Tbx6 (GenBank accession no. NM_011538), mouse T (GenBank accession no. NM_009309), mouse Eomesodermin (GenBank accession no. NM_010136), chick TbxL/Tbx6 (GenBank accession no. AB193180), chick Brachyury (GenBank accession no. U25176), X. tropicalis maternal VegT (GenBank accession no. AB451530), X. tropicalis zygotic VegT (GenBank accession no. AB451530), X. tropicalis Tbx6 (GenBank accession no. NM_001007994), X. tropicalis Xbra (GenBank accession no. BC081350), X. tropicalis Eomesodermin (GenBank accession no. NM_001128652), zebrafish Spadetail/Tbx16 (GenBank accession no. AF077225), zebrafish Tbx6 (GenBank accession no. U80951), zebrafish No tail (GenBank accession no. AB088068), zebrafish Eomesodermin a (GenBank accession no. NM_131679), and zebrafish Eomesodermin b (GenBank accession no. NM_001083575) were tested. Zebrafish Tbx5 (GenBank accession no. NM_130915) was used as the outgroup. (B) Genomic structure of the X. tropicalis VegT locus. First exon of mVegT, first exon of zVegT, and common exons of both variants are indicated as orange, green, and red boxes, respectively. (C) Comparison of the exon structure of genes in the VegT/Spadetail subfamily between six vertebrate genomes. The numbers shown on the left side of the box indicate the base pair size of each exon. (D) Conservation of synteny. By using Metazome, the flanking upstream and downstream genes of the putative X. tropicalis VegT orthologs were compared between six vertebrates. This set of genes is comprised of common orthologous genes among five vertebrate species including X. tropicalis, chick, fugu, medaka, and stickleback. Red arrows indicate the locus of the VegT ortholog. The gene and the transcriptional orientation are indicated by the color and direction of the arrow, respectively. (E-G) X. tropicalis zVegT expression patterns at stage 10, 11, and 12. The antisense probe for WISH recognized both mVegT and zVegT. Panels at the left and right show the lateral and vegetal views with the dorsal side up, respectively. |
