High impact information on Chordata

• Taspase1 coevolved with MLL/trithorax as Arthropoda and Chordata emerged from Metazoa suggesting that Taspase1 originated to regulate complex segmental body plans in higher organisms [1].
• Expression of engrailed proteins in arthropods, annelids, and chordates [2].
• It is probable that renin granules were present in the kidneys of ancestral chordates before divergence in the evolution of actinopterygian fish and tetrapods occurred [3].
• In conclusion, the CCK/gastrin family appears to be represented in most, if not all, chordates, to which group it may also be limited [4].
• By far, the creatine phosphate/creatine kinase (CP/CK) system, which is found in the vertebrates and is widely distributed throughout the lower chordates and invertebrates, is the most extensively studied phosphagen system [5].

Biological context of Chordata

• From the ancestral NK gene cluster, only the Tlx-Lbx and NK3-NK4 linkages have been retained in chordates [6].
• The existence of two MyoD family proteins that are differentially expressed during ascidian embryogenesis has novel parallels to vertebrate muscle development and may reflect conserved myogenic regulatory mechanisms among chordates [7].
• The purpose of this study was to examine the conservation of functional domains (including the uracil, flavine adenine dinucleotide and NADPH binding sites) across three phyla (Chordata, Arthropoda and Nematoda) and the conservation of regions corresponding to the previously reported mutations [8].
• Phylogenetic analysis was carried out using 14 translated Tf nucleotide sequences, and the derived evolutionary tree shows that at least three gene duplication events have occurred during Tf evolution, one of which generated the N- and C-terminal domains and occurred before separation of arthropods and chordates [9].
• Using the Ciona complete genome sequence and EST sequence data, we present here an initial and exhaustive search in non-vertebrate chordates, Ciona intestinalis for the family members as well as homologs or orthologs that are involved in PCP/CE signaling cascades [10].

Anatomical context of Chordata

• Brachyury is a sequence-specific transcriptional activator that is essential for notochord differentiation in a variety of chordates [11].
• Accordingly, a prominent conserved feature of pitx genes in chordates is their early expression in the anterior neural boundary (ANB) and oral ectoderm, also known as the stomodaeum [12].
• Also, SCO-spondin makes part of Reissner's fiber, a phylogenetically and ontogenetically conserved structure present in the central canal of the spinal cord of chordates [13].
• Gap junctions, composed of connexin proteins in chordates, are the most ubiquitous form of intercellular communication [14].
• TEPP, a new gene specifically expressed in testis, prostate, and placenta and well conserved in chordates [15].

Associations of Chordata with chemical compounds

• Tunicates represent the most primitive of the chordates, and there are data supporting a role for thyroid hormone in their metamorphosis, but no data are available on TRs in this genus; hence, we have studied Ciona intestinalis [16].
• Here we show that the emergence of protamines in chordates occurred very quickly, as a result of the conversion of a lysine-rich histone H1 to an arginine-rich protamine [17].
• Based on a phylogenetic analysis, we divided this gene family into 43 subfamilies and found that at least 19 tyrosine kinases were likely present in the common ancestor of chordates, arthropods, and nematodes [18].
• Recognizing RA signaling as a potential mechanism patterning cardiac segments, we propose to use it as a tool to scrutinize the phylogenetic origins of cardiac chambers within chordates [19].
• The "calcichordate" theory interprets an extinct group of calcite-plated invertebrates, the stylophorans, as chordates [20].

Gene context of Chordata

• The role of TGF beta signaling in the formation of the dorsal nervous system is conserved between Drosophila and chordates [21].
• Based on these observations and on results from molecular phylogenetic and hybridization analyses, we suggest that triplication of the tyrosinase family occurred during the early radiation of chordates [22].
• Ci-pitx and vertebrate pitx2 genes display remarkably similar exon usage and organization, suggesting ancestry of the pitx transcriptional unit and regulation in chordates [12].
• The unique, conserved aspects of annexin A13 primary structure, gene organization, and genetic maps identify it as the probable common ancestor of all vertebrate annexins, beginning with the sequential duplication to annexins A7 and A11 approximately 700 MYA, before the emergence of chordates [23].
• To investigate the distribution of Hox 8-like genes outside the chordates, we used the polymerase chain reaction and degenerate Hox 8 primers to screen genomic DNA of the purple sea urchin (Strongylocentrotus purpuratus, Phylum Echinodermata) [24].

Analytical, diagnostic and therapeutic context of Chordata

• Programmed cell death (PCD) in the ascidian species Ciona intestinalis (Tunicata; Chordata) is investigated from early larvae to juvenile stages, by means of digoxigenin-based terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick end labeling (TUNEL) technique [25].

References