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We report the first extended culture system for analysing zebrafish (Danio rerio) embryogenesis with which we demonstrate neural induction and anteroposterior patterning. Explants from the animal pole region of blastula embryos ('animal caps') survived for at least two days and increased in cell number. Mesodermal and neural-specific genes were not(More)
The interaction of the T cell receptor for antigen (TCR) with its antigen-major histocompatibility complex ligand is difficult to study because both are cell surface multimers. The TCR consists of two chains (alpha and beta) that are complexed to the five or more nonpolymorphic CD3 polypeptides. A soluble form of the TCR was engineered by replacing the(More)
Hox proteins form complexes with Pbx and Meis cofactors to control gene expression, but the role of Meis is unclear. We demonstrate that Hoxb1-regulated promoters are highly acetylated on histone H4 (AcH4) and occupied by Hoxb1, Pbx, and Meis in zebrafish tissues where these promoters are active. Inhibition of Meis blocks gene expression and reduces AcH4(More)
Hox transcription factors (TFs) are essential for vertebrate development, but how these evolutionary conserved proteins function in vivo remains unclear. Because Hox proteins have notoriously low binding specificity, they are believed to bind with cofactors, mainly homeodomain TFs Pbx and Meis, to select their specific targets. We mapped binding of Meis,(More)
pbx genes encode homeodomain-containing transcriptional regulators that interact with other proteins to control embryogenesis and tumorigenesis. We present the characterization of a zebrafish pbx CDNA that appears to encode a novel family member, pbx4. pbx4 RNA is maternally deposited and is detected throughout the zebrafish embryo during blastula stages.(More)
The progression of T cells from a quiescent or resting state to fully activated, proliferating cells is a crucial step in the initiation of an immune response. We have developed an in vitro system to study the requirements for triggering or hindering this pathway by using naive T cells derived from T-cell antigen receptor alpha beta transgenic animals and(More)
We have analyzed the roles of cell contact during determination of the outermost enveloping layer (EVL) and deeper neurectoderm in zebrafish embryos. Outer cells, but not deeper cells, are specified to express the EVL-specific marker, cyt1 by late blastula. EVL specification requires cell contact or close cell proximity, because cyt1 is not expressed after(More)
In order to understand anteroposterior axis formation in vertebrates, we have used subtractive hybridization to clone genes expressed posteriorly in the zebrafish gastrula-stage embryo. Here we report the initial characterization of eight clones isolated from this screen. We find that all eight genes are expressed in posteriorly restricted domains,(More)
The zebrafish nlz gene has a rostral expression limit at the presumptive rhombomere (r) 3/r4 boundary during gastrula stages, and its expression progressively expands rostrally to encompass both r3 and r2 by segmentation stages, suggesting a role for nlz in hindbrain development. We find that Nlz is a nuclear protein that associates with the corepressor(More)
In this study, we first cloned nlz2, a second zebrafish member of the nlz-related zinc-finger gene family. nlz2 was expressed together with nlz1 in a broad posterior domain during gastrula stages as well as at the midbrain-hindbrain boundary and in the hindbrain caudal to rhombomere 4 during segmentation. nlz2 was also expressed in regions distinct from(More)