Project description:Zic3 regulates early embryonic patterning in vertebrates. Its loss-of-function disrupts gastrulation, left-right patterning, and neurogenesis. We use the zebrafish as a model to study the developmental role of Zic3 in vivo. Using a combination of two genomics approaches – ChIP-seq and microarray, we identified Zic3 targets, which include genes from the Nodal and Wnt pathways, and show for the first time cis-regulation of these genes by Zic3 using in vivo enhancer assay. We uncovered a previously unrecognized link between Zic3 and the non-canonical Wnt pathway in gastrulation and left-right patterning, and identified neural pre-pattern genes as Zic3 targets during the early steps of neural induction. Zic3 preferably binds to distal intergenic regions, some of which contain evolutionarily conserved functional enhancers. Our study establishes the zebrafish as an excellent model for genome-wide study of a transcription factor in vivo. Zic3 ChIP of wild type and sqet33 transgenic
Project description:Here we compare transcriptomic data generated using Affymetrix one-cycle (standard labelling protocol), two-cycle (small-sample protocol) and IVT-Express protocols with the Affymetrix ATH1 array using Arabidopsis root samples. Results obtained with each protocol are broadly similar. However, we show that there are 35 probe sets (of a total of 22810) that are misrepresented in the two-cycle data sets. Of these, 33 probe sets were classed as mis-amplified when comparisons of two independent publicly available data sets were undertaken.
Project description:TÜAB zebrafish were maintained at 28.5 °C in in 1x Danieau solution (58 mM NaCl, 0.7 mM KCl, 0.4 mM MgSO4, 0.6 mM Ca (NO3)2, 5 mM HEPES, pH 7.6, 0.0001 % Methylene blue). Morpholinos (Gene Tools, Philomath, OR) were designed against Danio rerio lin-9 homolog (Genebank accession NM_001044946). The morpholino (MO) sequences were MO-E1 5´-GTTAGTTTTATTACTCACTCTCGTC-3´ and 5-base mismatch morpholino MO-E1mis 5´-GTTACTTTTAATACTGACTGTCCTC-3´. 7 ng of morpholinos were injected into one cell-stage embryos. 20 embryos per condition (MO E1; MO E1mis) were pooled for RNA purification 24 h post fertilization. Using the two color Quick-Amp Labeling Kit (Agilent; 5190-0444) 100 ng of total RNA were used for cDNA synthesis, mRNA amplification and labeling according to manufacturers instructions. Transcriptional profiling was done on a zebrafish oligo array (Agilent; G2519F AMADID 019161) in a 4 x 44K slide format and analyzed as described before.<br>
Project description:Ciz1 promotes initiation of mammalian DNA replication and is present within nuclear matrix associated DNA replication factories. Depletion of Ciz1 from normal and cancer cells restrains entry to S phase and inhibits cell proliferation. Several alternative splicing events with putative functional consequences have been identified and reported, but many more variants are predicted to exist based on publicly available mRNAs and expressed sequence tags. Here we report the development and validation of a custom exon and exon-junction microarray focused on the human Ciz1 gene, capable of reproducible detection of differential splice-variant expression. Using a pair of paediatric cancer cell lines and a pool of eight normal lines as reference, the array identified expected and novel Ciz1 splicing events. One novel variant (delta 8-12) that encodes a predicted protein lacking key functional sites, was validated by quantitative RT-PCR and found to be over-represented in a range of other cancer cell lines, and over half of a panel of primary lung tumours.
Project description:Changes in tissue homeostasis, acquisition of invasive cell characteristics and tumor formation can often be linked to the loss of epithelial cell polarity. In carcinogenesis, the grade of neoplasia correlates with impaired cell polarity. In Drosophila, lgl, dlg and scribble, which are components of the epithelial apico-basal cell polarity machinery, act as tumor suppressors and orthologs of this evolutionary conserved pathway are lost in human carcinoma with high frequency. However, a mechanistic link between neoplasia and vertebrate orthologs of these tumor suppressor genes remains to be fully explored at the organismal level. Here, we show that the pen/lgl2 mutant phenotype shares two key cellular and molecular features of mammalian malignancy: cell autonomous epidermal neoplasia and epithelial-to-mesenchymal-transition (EMT) of basal epidermal cells including the differential expression of several regulators of EMT. Further we found that epidermal neoplasia and EMT in pen/lgl2 mutant epidermal cells is promoted by ErbB signalling, a pathway of high significance in human carcinomas. Intriguingly, EMT in the pen/lgl2 mutant is facilitated specifically by ErbB2 mediated E-cadherin mislocalization and not via canonical snail dependent down-regulation of E-cadherin expression. Our data reveal that pen/lgl2 functions as a tumor suppressor gene in vertebrates, establishing zebrafish pen/lgl2 mutants as a valuable cancer model.