Figure 4: H. oligactis tumour-bearing polyps have a unique gene expression profile.
From: Naturally occurring tumours in the basal metazoan Hydra
(a) Principal component analysis separates transcriptomes of tumour, oogenesis-induced (female) and control H. oligactis polyps. Percentage of explained variance is indicated for each component. (b) Venn diagram representing differentially regulated (>3.0-fold change) contigs in tumour polyps compared with control and female polyps. The overlap between both groups contains 417 contigs and makes a specific signature of the tumour transcriptome. Among these contigs, 196 uniquely correspond to H. magnipapillata gene models, and 44 of them show homology to genes implicated in mammalian malignancies. (c–e) Whole-mount in situ hybridization with DIG-labelled antisense RNA probe specific for Hydra homologue of translationally controlled tumour-protein (tpt1, p23) gene confirms, that tpt1 is expressed exclusively in tumorous polyps (tumour, c), with no specific signal being detected in normal asexual (control, d) or oogenesis-induced (female, e) polyps. Hybridization with sense-probe (insets) reveals no signal, confirming detection specificity. Scale bar, 300 μm.
