A cnidarian homologue of translationally controlled tumor protein (P23/TCTP).
A protein homologous to P23, or translationally controlled tumor protein (TCTP), was cloned in Hydra vulgaris, the most ancient type of metazoan from which P23/TCTP has been characterized to date. Hydra P23/TCTP is composed of 184 amino acids and is encoded by a single mRNA of 700 bp. This invertebrate P23/TCTP is well conserved compared to those of other invertebrate and vertebrate species. Expression of Hydra P23/TCTP was confirmed by western blot of Hydra cell lysates using a polyclonal antibody against murine recombinant P23/TCTP. Spatial distribution of P23/TCTP mRNA and protein in Hydra was studied using in situ hybridization and immunostaining, respectively. Hydra P23/TCTP expression along the longitudinal body axis is regulated at both the transcriptional and the translational level. High levels of P23/TCTP mRNA were detected in a subpopulation of cells in the body column. In contrast, no mRNA was evident in the differentiated cells of the head and the foot regions. Coincidentally, P23/TCTP protein also concentrates to the body column, with no detectable protein in the head and foot region. However, despite the existence of P23/TCTP mRNA in both the ectoderm and endoderm in the body column, its protein is localized to the endodermal cells, suggesting a regulatory mechanism at the translational level. Taken together, the expression pattern of P23/TCTP in Hydra correlates with regions in which cell proliferation is actively occurring and its expression is excluded from regions where terminal differentiation has occurred.
Yan
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Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS 66160-7400, USA.
Fei
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Bridge
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Sarras
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D000595:Amino Acid Sequence; D000818:Animals; D014408:Biomarkers, Tumor; D002135:Calcium-Binding Proteins / Q000737:chemistry / Q000235:genetics*; D003001:Cloning, Molecular; D018076:DNA, Complementary; D006801:Humans; D006829:Hydra / Q000235:genetics*; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid; D000090324:Tumor Protein, Translationally-Controlled 1
D014408:Biomarkers, Tumor; D002135:Calcium-Binding Proteins; D018076:DNA, Complementary; C000715647:TPT1 protein, human; D000090324:Tumor Protein, Translationally-Controlled 1