High impact information on tbx1

• Mutant analysis in the zebrafish Danio rerio has demonstrated distinct developmental roles for the T-box transcription factor Spadetail (Spt) and the Nodal-receptor cofactor One-Eyed Pinhead (Oep) in the formation of mesoderm and endoderm [1].
• Finally, genetic analysis reveals novel roles for the T-box transcription factor no tail and the Nodal signaling pathway as upstream regulators of lrdr1 expression and KV morphogenesis [2].
• Using cell transplantation studies, we demonstrate that vgo/tbx1 acts cell autonomously in the pharyngeal mesendoderm and influences the development of neural crest-derived cartilages secondarily [3].
• We provide both phenotypic and genetic evidence that these Fgf signaling components interact with no tail and spadetail, two zebrafish T-box transcription factors that are required for the development of all posterior mesoderm [4].
• T-box genes encode transcriptional regulators that control many aspects of embryonic development [5].

Biological context of tbx1

• Within this 7-kb distal regulatory region, we delineated a 1300-bp region with a cluster of consensus binding sites for T-box transcription factors [6].
• Thus, GATA-4 regulatory elements control gene expression differentially along the rostro-caudal axis, and T-box binding elements in the GATA-4 promoter contribute to heart-specific expression [6].

Anatomical context of tbx1

• Through the stage of embryonic shield formation, tbx1 expression is restricted to the hypoblast, in the region of cells fated to become head and lateral plate mesoderm and pharyngeal endoderm [7].
• At 18 hpf, when the heart tube is beginning to assemble, three domains of tbx1 expression can be seen: cardiac precursors, pharyngeal arch precursors and otic vesicle [7].
• Expression of zebrafish tbx1 by whole-mount in situ hybridization was first detected at 40% epiboly, 5.0 hours post fertilization (hpf) in the dorsal blastoderm margin [7].
• The recently identified zebrafish T-box gene hrT is expressed in the developing heart and in the endothelial cells forming the dorsal aorta [8].
• Two T-box genes are expressed in the developing telencephalon of several vertebrate species, including amphibia, birds and mammals [9].

Other interactions of tbx1

• The T-box gene eomesodermin (eomes) has been implicated in mesoderm specification and patterning in both zebrafish and frog [10].
• The zebrafish T-box transcription factors spadetail (spt) and the brachyury ortholog no tail (ntl) are together essential for posterior mesoderm formation [11].
• Cloning of zebrafish T-box genes tbx15 and tbx18 and their expression during embryonic development [12].
• A detailed analysis of the expression of tbr1 and eom in the brain of 4 day old larvae shows that the two T-box genes are differentially expressed in various cell populations of the developing brain [9].
• We report on a new zebrafish T-box-containing gene, tbx16 [13].

References