Charles Sagerström

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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)
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)
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)
Subtractive cloning is a powerful technique for isolating genes expressed or present in one cell population but not in another. This method and a related one termed positive selection have their origins in nucleic acid reassociation techniques. We discuss the history of subtractive techniques, and fundamental information about the nucleic acid composition(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)
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)
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)
Many Hox proteins are thought to require Pbx and Meis co-factors to specify cell identity during embryogenesis. Here we demonstrate that Meis3 synergizes with Pbx4 and Hoxb1b in promoting hindbrain fates in the zebrafish. We find that Hoxb1b and Pbx4 act together to induce ectopic hoxb1a expression in rhombomere 2 of the hindbrain. In contrast, Hoxb1b and(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)
C2H2 zinc finger proteins make up one of the largest protein families in eukaryotic organisms. Recent study in several different systems has identified a set of novel zinc finger proteins that appear to form a distinct subfamily that we have named the NET family. Members of the NET family (Noc, Nlz, Elbow, and Tlp-1) share two protein motifs--a buttonhead(More)